Graded Mesh Refinement and Error Estimates of Higher Order for DGFE-solutions of Elliptic Boundary Value Problems in Polygons
|
|
- August Lyons
- 5 years ago
- Views:
Transcription
1 Graded Mesh Refinement and Error Estimates of Higher Order for DGFE-solutions of Elliptic Boundary Value Problems in Polygons Anna-Margarete Sändig, Miloslav Feistauer University Stuttgart, IANS Journées Singulières Augmentes en l honneur de Martin Costabel University of Rennes, August 26 to 30, 2013 Anna-Margarete Sändig Graded Mesh Refinement 1/19
2 1 Continuous problem 2 Discontinuous Galerkin Discretization 3 Error Estimates Anna-Margarete Sändig Graded Mesh Refinement 2/19
3 Preliminaries Finite volume method used in computational fluid dynamics, piecewise constant (and hence, discontinuous) approximations. Anna-Margarete Sändig Graded Mesh Refinement 3/19
4 Preliminaries Finite volume method used in computational fluid dynamics, piecewise constant (and hence, discontinuous) approximations. Conforming Galerkin finite element techniques used in structure mechanics, continuous piecewise polynomial approximations on a finite element mesh. Anna-Margarete Sändig Graded Mesh Refinement 3/19
5 Preliminaries Finite volume method used in computational fluid dynamics, piecewise constant (and hence, discontinuous) approximations. Conforming Galerkin finite element techniques used in structure mechanics, continuous piecewise polynomial approximations on a finite element mesh. Discontinuous Galerkin finite element method (DGFEM), piecewise polynomial approximations on a finite element mesh without any requirement on the continuity between neighbouring elements. Anna-Margarete Sändig Graded Mesh Refinement 3/19
6 Preliminaries Finite volume method used in computational fluid dynamics, piecewise constant (and hence, discontinuous) approximations. Conforming Galerkin finite element techniques used in structure mechanics, continuous piecewise polynomial approximations on a finite element mesh. Discontinuous Galerkin finite element method (DGFEM), piecewise polynomial approximations on a finite element mesh without any requirement on the continuity between neighbouring elements. Very flexible schemes. Anna-Margarete Sändig Graded Mesh Refinement 3/19
7 Preliminaries Finite volume method used in computational fluid dynamics, piecewise constant (and hence, discontinuous) approximations. Conforming Galerkin finite element techniques used in structure mechanics, continuous piecewise polynomial approximations on a finite element mesh. Discontinuous Galerkin finite element method (DGFEM), piecewise polynomial approximations on a finite element mesh without any requirement on the continuity between neighbouring elements. Very flexible schemes. Error estimates for DGFE-solutions are well investigated if one assumes that the exact solution is sufficiently regular. Some papers (Wihler 02, Brenner 09) about less regular solutions. Here, polygons, mixed boundary conditions, weighted spaces, Sobolev-Slobodetskii spaces. Anna-Margarete Sändig Graded Mesh Refinement 3/19
8 01 Linear elliptic boundary value problem P 3 Ω R 2 polygon with boundary Ω = Γ D Γ N, where Γ D Γ N =, meas{γ D } > 0, n = (n 1, n 2 ) unit outward normal to Ω. Γ N Γ 01 P 2 P 1 r D Ω ω Γ N P 4 Γ D P 5 Anna-Margarete Sändig Graded Mesh Refinement 4/19
9 01 Linear elliptic boundary value problem P 3 Ω R 2 polygon with boundary Ω = Γ D Γ N, where Γ D Γ N =, meas{γ D } > 0, n = (n 1, n 2 ) unit outward normal to Ω. Γ N Γ 01 P 2 P 1 r D Ω ω Γ N P 4 Γ D P 5 Lu = L(x, D x )u = 2 i,j=1 x i B 2 (x, D x )u = ( a ij (x) u ) + c(x)u = f in Ω, x j B 1 (x, D x )u = u = 0 on Γ D, 2 a ij (x) u n i = q x j on Γ N. i,j=1 Anna-Margarete Sändig Graded Mesh Refinement 4/19
10 Weak formulation Find u V = {v H 1 (Ω) : v ΓD = 0} such that Anna-Margarete Sändig Graded Mesh Refinement 5/19
11 Weak formulation Find u V = {v H 1 (Ω) : v ΓD = 0} such that a(u, v) = (f, v) + (q, v) ΓN v V, Anna-Margarete Sändig Graded Mesh Refinement 5/19
12 Weak formulation Find u V = {v H 1 (Ω) : v ΓD = 0} such that a(u, v) = (f, v) + (q, v) ΓN v V, a(u, v) = (f, v) = Ω Ω 2 u v a ij + cuv dx, x j x i i,j=1 fv dx, (q, v) ΓN = qv dv, Γ N Anna-Margarete Sändig Graded Mesh Refinement 5/19
13 Weak formulation Find u V = {v H 1 (Ω) : v ΓD = 0} such that a(u, v) = (f, v) + (q, v) ΓN v V, a(u, v) = (f, v) = Ω Ω 2 u v a ij + cuv dx, x j x i i,j=1 fv dx, (q, v) ΓN = qv dv, Γ N a ij, c, f, q sufficiently smooth. Assume, Lax-Milgram lemma holds and therefore, an unique weak solution u V exists. Anna-Margarete Sändig Graded Mesh Refinement 5/19
14 Regularity To which Sobolev-Slobodetskii spaces or weighted Sobolevs spaces belongs the weak solution? Anna-Margarete Sändig Graded Mesh Refinement 6/19
15 Regularity To which Sobolev-Slobodetskii spaces or weighted Sobolevs spaces belongs the weak solution? Sobolev-Slobodetskii spaces H k+γ (Ω),γ (0, 1), is defined as the subspace of H k (Ω) formed by all functions v for which the seminorm is finite, that means Anna-Margarete Sändig Graded Mesh Refinement 6/19
16 Regularity To which Sobolev-Slobodetskii spaces or weighted Sobolevs spaces belongs the weak solution? Sobolev-Slobodetskii spaces H k+γ (Ω),γ (0, 1), is defined as the subspace of H k (Ω) formed by all functions v for which the seminorm is finite, that means v H k+γ (Ω) = α =k Ω Ω D α v(x) D α v(y) 2 x y 2+2γ dxdy 1/2 < +. Anna-Margarete Sändig Graded Mesh Refinement 6/19
17 Regularity To which Sobolev-Slobodetskii spaces or weighted Sobolevs spaces belongs the weak solution? Sobolev-Slobodetskii spaces H k+γ (Ω),γ (0, 1), is defined as the subspace of H k (Ω) formed by all functions v for which the seminorm is finite, that means v H k+γ (Ω) = α =k The norm is defined as Ω Ω v H k+γ (Ω) = D α v(x) D α v(y) 2 x y 2+2γ dxdy ( v 2 H k (Ω) + v 2 H k+γ (Ω)) 1/2. 1/2 < +. Anna-Margarete Sändig Graded Mesh Refinement 6/19
18 Weighted Sobolev spaces Let be M = {P i } i=1,...,i the set of irregular points, β = (β 1, β 2,..., β I ), r = r(x) = dist(x, M), r i = x P i and C M (Ω) := {u C (Ω) : supp u M = }. Anna-Margarete Sändig Graded Mesh Refinement 7/19
19 Weighted Sobolev spaces Let be M = {P i } i=1,...,i the set of irregular points, β = (β 1, β 2,..., β I ), r = r(x) = dist(x, M), r i = x P i and C M (Ω) := {u C (Ω) : supp u M = }. The space V k,p β (Ω), 1 p <, is the closure of the set C M (Ω) with respect to the norm 1/p u V k,p β (Ω) = Ω i=1,...,i r pβ i i α k r p( k+ α ) D α u p dx. Anna-Margarete Sändig Graded Mesh Refinement 7/19
20 Weighted Sobolev spaces Let be M = {P i } i=1,...,i the set of irregular points, β = (β 1, β 2,..., β I ), r = r(x) = dist(x, M), r i = x P i and C M (Ω) := {u C (Ω) : supp u M = }. The space V k,p β (Ω), 1 p <, is the closure of the set C M (Ω) with respect to the norm 1/p u V k,p β (Ω) = Ω i=1,...,i r pβ i i α k r p( k+ α ) D α u p dx. In U(P i ) the norm is equivalent to ( D α u p dx U(Pi ) α k r p(β i k+ α ) i ) 1/p Anna-Margarete Sändig Graded Mesh Refinement 7/19
21 Weighted Sobolev spaces Let be M = {P i } i=1,...,i the set of irregular points, β = (β 1, β 2,..., β I ), r = r(x) = dist(x, M), r i = x P i and C M (Ω) := {u C (Ω) : supp u M = }. The space V k,p β (Ω), 1 p <, is the closure of the set C M (Ω) with respect to the norm 1/p u V k,p β (Ω) = Ω i=1,...,i r pβ i i α k r p( k+ α ) D α u p dx. In U(P i ) the norm is equivalent to ( D α u p dx U(Pi ) α k r p(β i k+ α ) i ) 1/p If β 1 = β 2 =... = β I = β, then we write shortly V k,p β (Ω) with ( u k,p = 1/p V β (Ω) Ω α k r p(β k+ α ) D α u dx) p. Anna-Margarete Sändig Graded Mesh Refinement 7/19
22 Weighted Sobolev spaces Let be M = {P i } i=1,...,i the set of irregular points, β = (β 1, β 2,..., β I ), r = r(x) = dist(x, M), r i = x P i and C M (Ω) := {u C (Ω) : supp u M = }. The space V k,p β (Ω), 1 p <, is the closure of the set C M (Ω) with respect to the norm 1/p u V k,p β (Ω) = Ω i=1,...,i r pβ i i α k r p( k+ α ) D α u p dx. In U(P i ) the norm is equivalent to ( D α u p dx U(Pi ) α k r p(β i k+ α ) i ) 1/p If β 1 = β 2 =... = β I = β, then we write shortly V k,p β (Ω) with ( u k,p = 1/p V β (Ω) Ω α k r p(β k+ α ) D α u dx) p. Babushka/Guo, Wihler have used weights for higher derivatives only. Anna-Margarete Sändig Graded Mesh Refinement 7/19
23 It is well known, that the distribution of the eigenvalues of a corresponding generalized eigenvalue problem (principal parts with frozen coefficients, localization, Mellin transform (r i r i α)) characterizes the regularity in each irregular boundary point. Anna-Margarete Sändig Graded Mesh Refinement 8/19
24 It is well known, that the distribution of the eigenvalues of a corresponding generalized eigenvalue problem (principal parts with frozen coefficients, localization, Mellin transform (r i r i α)) characterizes the regularity in each irregular boundary point. For an irregular point P i we consider an eigenvalue α0 i of the Mellin transformed eigenvalue problem with maximal real part, such that the strip 0 < R(α) < R(α0 i ) Anna-Margarete Sändig Graded Mesh Refinement 8/19
25 It is well known, that the distribution of the eigenvalues of a corresponding generalized eigenvalue problem (principal parts with frozen coefficients, localization, Mellin transform (r i r i α)) characterizes the regularity in each irregular boundary point. For an irregular point P i we consider an eigenvalue α0 i of the Mellin transformed eigenvalue problem with maximal real part, such that the strip 0 < R(α) < R(α0 i )is free of eigenvalues. We set H0 i = R(αi 0 ), H0 = {H0 1,..., HI 0 }. Anna-Margarete Sändig Graded Mesh Refinement 8/19
26 It is well known, that the distribution of the eigenvalues of a corresponding generalized eigenvalue problem (principal parts with frozen coefficients, localization, Mellin transform (r i r i α)) characterizes the regularity in each irregular boundary point. For an irregular point P i we consider an eigenvalue α0 i of the Mellin transformed eigenvalue problem with maximal real part, such that the strip 0 < R(α) < R(α0 i )is free of eigenvalues. We set H0 i = R(αi 0 ), H0 = {H0 1,..., HI 0 }. By some calculations (linear principal axes transformation, anisotropic to isotropic Laplacian, back transformation) we get H0 i > 1 4 for 0 < ωi 0 < 2π, Hi 0 > 1 2 for ωi 0 < π, Hi 0 = 1 2 for ω0 i = π. More precisely, H0 i = π for D-D conditions. λ i 1 tan ω0 i ) arctan( λ i 2 Anna-Margarete Sändig Graded Mesh Refinement 8/19
27 ondratjev 1967 Theorem Assume, f V k,2 1 k+ 1 H 2 (Ω) and q V,2 0 +ε+k 1 H (Γ 0 N), where ε > 0 +ε+k is an arbitrarily small real number, k is an integer. Then the weak solution u V is contained in V 2+k,2 1 H (Ω). 0 +ε+k Anna-Margarete Sändig Graded Mesh Refinement 9/19
28 ondratjev 1967 Theorem Assume, f V k,2 1 k+ 1 H 2 (Ω) and q V,2 0 +ε+k 1 H (Γ 0 N), where ε > 0 +ε+k is an arbitrarily small real number, k is an integer. Then the weak solution u V is contained in V 2+k,2 1 H (Ω). 0 +ε+k Two possibilities for simplification with respect to the number of irregular boundary points: We use a localization and consider different graded mesh refinements separately for individual irregular points. We set H 0 = min{h0 i, i = 1,, I } and consider the same (finest) graded mesh refinement for every singular point. Then, u V 2+k,2 1 H 0 +ε+k (Ω) and, furthermore u H1+H 0 ε (Ω). Anna-Margarete Sändig Graded Mesh Refinement 9/19
29 Discontinuous Galerkin Discretization {T h } h (0,h0 ) family of partitions with standard properties, h mesh parameter, F h = F D h F I h subset of faces of all elements T h. Anna-Margarete Sändig Graded Mesh Refinement 10/19
30 Discontinuous Galerkin Discretization {T h } h (0,h0 ) family of partitions with standard properties, h mesh parameter, F h = F D h F I h subset of faces of all elements T h. Consider broken Sobolev-Slobodetskii spaces H s (Ω, T h ) = {v; v H s () T h } equipped with the seminorm v H s (Ω,T h ) = ( T h v 2 H s ()) 1/2, and broken weighted spaces V k,2 β (Ω, T h). Anna-Margarete Sändig Graded Mesh Refinement 10/19
31 Discontinuous Galerkin Discretization {T h } h (0,h0 ) family of partitions with standard properties, h mesh parameter, F h = F D h F I h subset of faces of all elements T h. Consider broken Sobolev-Slobodetskii spaces H s (Ω, T h ) = {v; v H s () T h } equipped with the seminorm v H s (Ω,T h ) = ( T h v 2 H s ()) 1/2, and broken weighted spaces V k,2 β (Ω, T h). Using Greens formula we get A h (u, v) = l h (v) defined on X X, Anna-Margarete Sändig Graded Mesh Refinement 10/19
32 Discontinuous Galerkin Discretization {T h } h (0,h0 ) family of partitions with standard properties, h mesh parameter, F h = F D h F I h subset of faces of all elements T h. Consider broken Sobolev-Slobodetskii spaces H s (Ω, T h ) = {v; v H s () T h } equipped with the seminorm v H s (Ω,T h ) = ( T h v 2 H s ()) 1/2, and broken weighted spaces V k,2 β (Ω, T h). Using Greens formula we get A h (u, v) = l h (v) defined on X X, where X = H 1+γ (Ω, T h ) with γ = H 0 ε ( 1, 1) or 2 Anna-Margarete Sändig Graded Mesh Refinement 10/19
33 Discontinuous Galerkin Discretization {T h } h (0,h0 ) family of partitions with standard properties, h mesh parameter, F h = F D h F I h subset of faces of all elements T h. Consider broken Sobolev-Slobodetskii spaces H s (Ω, T h ) = {v; v H s () T h } equipped with the seminorm v H s (Ω,T h ) = ( T h v 2 H s ()) 1/2, and broken weighted spaces V k,2 β (Ω, T h). Using Greens formula we get A h (u, v) = l h (v) defined on X X, where X = H 1+γ (Ω, T h ) with γ = H 0 ε ( 1, 1) or 2 X = V 2,2 β+1 (Ω, T h) with β = H 0 + ε ( 1, 0). Anna-Margarete Sändig Graded Mesh Refinement 10/19
34 Discontinuous Galerkin Discretization {T h } h (0,h0 ) family of partitions with standard properties, h mesh parameter, F h = F D h F I h subset of faces of all elements T h. Consider broken Sobolev-Slobodetskii spaces H s (Ω, T h ) = {v; v H s () T h } equipped with the seminorm v H s (Ω,T h ) = ( T h v 2 H s ()) 1/2, and broken weighted spaces V k,2 β (Ω, T h). Using Greens formula we get A h (u, v) = l h (v) defined on X X, where X = H 1+γ (Ω, T h ) with γ = H 0 ε ( 1, 1) or 2 X = V 2,2 β+1 (Ω, T h) with β = H 0 + ε ( 1, 0). A h (u, v) = a h (u, v) + µj h (u, v) l h (v) = fv dx + qv ds. Ω Γ N Anna-Margarete Sändig Graded Mesh Refinement 10/19
35 a h (w, v) = 2 w v a ij + cwv dx T x h i,j=1 j x i 2 w 2 a ij n Γ v i Γ F h I Γ x [v] + θ a ij n Γ i i,j=1 j x [w] ds i,j=1 j 2 w 2 a ij n Γ i Γ F h D Γ x v + θ v a ij n Γ i i,j=1 j x w ds, i,j=1 j Anna-Margarete Sändig Graded Mesh Refinement 11/19
36 a h (w, v) = 2 w v a ij + cwv dx T x h i,j=1 j x i 2 w 2 a ij n Γ v i Γ F h I Γ x [v] + θ a ij n Γ i i,j=1 j x [w] ds i,j=1 j 2 w 2 a ij n Γ i Γ F h D Γ x v + θ v a ij n Γ i i,j=1 j x w ds, i,j=1 j J h (w, v) = κ(γ)[w] [v] ds + κ(γ)wv ds, Γ F h I Γ Γ F h D Γ Anna-Margarete Sändig Graded Mesh Refinement 11/19
37 a h (w, v) = 2 w v a ij + cwv dx T x h i,j=1 j x i 2 w 2 a ij n Γ v i Γ F h I Γ x [v] + θ a ij n Γ i i,j=1 j x [w] ds i,j=1 j 2 w 2 a ij n Γ i Γ F h D Γ x v + θ v a ij n Γ i i,j=1 j x w ds, i,j=1 j J h (w, v) = κ(γ)[w] [v] ds + κ(γ)wv ds, Γ F h I Γ Γ F h D Γ ( J h are penalty terms, θ = 1(NIPG), θ = 0(IIPG), θ = 1(SIPG), v = 1 v (L) + v (R)), [v] = v (L) v (R). 2 Anna-Margarete Sändig Graded Mesh Refinement 11/19
38 a h (w, v) = 2 w v a ij + cwv dx T x h i,j=1 j x i 2 w 2 a ij n Γ v i Γ F h I Γ x [v] + θ a ij n Γ i i,j=1 j x [w] ds i,j=1 j 2 w 2 a ij n Γ i Γ F h D Γ x v + θ v a ij n Γ i i,j=1 j x w ds, i,j=1 j J h (w, v) = κ(γ)[w] [v] ds + κ(γ)wv ds, Γ F h I Γ Γ F h D Γ ( J h are penalty terms, θ = 1(NIPG), θ = 0(IIPG), θ = 1(SIPG), v = 1 v (L) + v (R)), [v] = v (L) v (R). 2 The approximate solution u h will be sought in the space of discontinuous piecewise polynomial functions of fixed degree p, S hp = {v L 2 (Ω); v P p (), T h }, such that A h (u h, v h ) = l h (v h ) v h S hp. Anna-Margarete Sändig Graded Mesh Refinement 11/19
39 Error estimates on regular meshes The error e h = u h u of the DG method satisfies the Galerkin orthogonality condition A h (e h, v h ) = 0 v h S hp. Anna-Margarete Sändig Graded Mesh Refinement 12/19
40 Error estimates on regular meshes The error e h = u h u of the DG method satisfies the Galerkin orthogonality condition A h (e h, v h ) = 0 v h S hp. We introduce the DG-norm in H 1 (Ω, T h ) ( w DG = w 2 H 1 (Ω,T h ) + J h(w, w) ) 1/2 Anna-Margarete Sändig Graded Mesh Refinement 12/19
41 Error estimates on regular meshes The error e h = u h u of the DG method satisfies the Galerkin orthogonality condition A h (e h, v h ) = 0 v h S hp. We introduce the DG-norm in H 1 (Ω, T h ) ( w DG = w 2 H 1 (Ω,T h ) + J h(w, w) ) 1/2 Theorem Let be the exact solution u H 1+γ (Ω), γ ( 1 2, 1) and u H 1+ν ( Ω), where Ω Ω with dist( Ω, M) > 0, ν = min(p, κ), κ is an integer, which depends on the smoothness of the loads. Then e h DG C ( h 2ν u 2 H ν+1 ( Ω) + h2γ u 2 H 1+γ (Ω)) 1/2. Anna-Margarete Sändig Graded Mesh Refinement 12/19
42 Error estimates on graded meshes Graded partitions Ω polygon with the set of irregular points M, h mesh parameter, {T h } h (0,h0 ) family of partitions. Anna-Margarete Sändig Graded Mesh Refinement 13/19
43 Error estimates on graded meshes Graded partitions Ω polygon with the set of irregular points M, h mesh parameter, {T h } h (0,h0 ) family of partitions. For T h we set h = diam(), h = max Th h, ρ is the radius of the largest circle inscribed into, r = dist(, M). Anna-Margarete Sändig Graded Mesh Refinement 13/19
44 Error estimates on graded meshes Graded partitions Ω polygon with the set of irregular points M, h mesh parameter, {T h } h (0,h0 ) family of partitions. For T h we set h = diam(), h = max Th h, ρ is the radius of the largest circle inscribed into, r = dist(, M). Furthermore, T h = Th M Th 0 : T h M, if M. Assume (a) {T h } h (0,h0 ) is regular: h / ρ C T h, h Anna-Margarete Sändig Graded Mesh Refinement 13/19
45 Error estimates on graded meshes Graded partitions Ω polygon with the set of irregular points M, h mesh parameter, {T h } h (0,h0 ) family of partitions. For T h we set h = diam(), h = max Th h, ρ is the radius of the largest circle inscribed into, r = dist(, M). Furthermore, T h = Th M Th 0 : T h M, if M. Assume (a) {T h } h (0,h0 ) is regular: h / ρ C T h is graded with respect to M : T h, h Anna-Margarete Sändig Graded Mesh Refinement 13/19
46 Error estimates on graded meshes Graded partitions Ω polygon with the set of irregular points M, h mesh parameter, {T h } h (0,h0 ) family of partitions. For T h we set h = diam(), h = max Th h, ρ is the radius of the largest circle inscribed into, r = dist(, M). Furthermore, T h = Th M Th 0 : T h M, if M. Assume (a) {T h } h (0,h0 ) is regular: h / ρ C T h is graded with respect to M : T h, h (b 1 ) if T M h, then C 1h 1/µ h C 1 h 1/µ, (b 2 ) if T 0 h, then C 2hr 1 µ h C 2 hr 1 µ, where µ (0, 1] is the grading parameter. Anna-Margarete Sändig Graded Mesh Refinement 13/19
47 Examples for graded partitions Radial partitions using layers (Oganesyan/Rukhovets 1979) Anna-Margarete Sändig Graded Mesh Refinement 14/19
48 Examples for graded partitions Radial partitions using layers (Oganesyan/Rukhovets 1979) N = 3, µ = 0.4, Apel 1996 Anna-Margarete Sändig Graded Mesh Refinement 14/19
49 Radial partitions using an initial triangulation (Raugel 1978) Anna-Margarete Sändig Graded Mesh Refinement 15/19
50 Radial partitions using an initial triangulation (Raugel 1978) N = 3, µ = 0.4, Apel 1996 Anna-Margarete Sändig Graded Mesh Refinement 15/19
51 Feistauer/Sändig 2012 Theorem Let Ω be a polygon, β = H 0 + ε, γ = H 0 ε ( 1 2, 1). Consider the exact solution u V 2+k,2 β+1+k (Ω) H1+γ (Ω) of the mixed problem and set p = k + 1. Anna-Margarete Sändig Graded Mesh Refinement 16/19
52 Feistauer/Sändig 2012 Theorem Let Ω be a polygon, β = H 0 + ε, γ = H 0 ε ( 1 2, 1). Consider the exact solution u V 2+k,2 β+1+k (Ω) H1+γ (Ω) of the mixed problem and set p = k + 1.Let {T h } h (0,h0 ) be a regular system of triangulations graded towards the set M. Then there exists a constant C > 0 such that Anna-Margarete Sändig Graded Mesh Refinement 16/19
53 Feistauer/Sändig 2012 Theorem Let Ω be a polygon, β = H 0 + ε, γ = H 0 ε ( 1 2, 1). Consider the exact solution u V 2+k,2 β+1+k (Ω) H1+γ (Ω) of the mixed problem and set p = k + 1.Let {T h } h (0,h0 ) be a regular system of triangulations graded towards the set M. Then there exists a constant C > 0 such that u u h DG Ch α ( u 2 V 2+k,2 β+1+k (Ω) + u 2 H 1+γ (Ω) α = with ε > 0 arbitrarily small. { k + 1 for µ < H 0 k+1, H 0 ε µ for µ H 0 k+1, ) 1/2, Anna-Margarete Sändig Graded Mesh Refinement 16/19
54 Main ideas of the proof For η = u I h u it holds ( ( e h DG C η 2 H 1 () + h 2 η 2 H 2 () + h 2 T 0 h + T M h η 2 L 2 () ( η 2 H 1 () + h 2γ η 2 H 1+γ () + h 2 η 2 L 2 ())) 1/2, h (0, h0). ) Anna-Margarete Sändig Graded Mesh Refinement 17/19
55 Main ideas of the proof For η = u I h u it holds ( ( e h DG C η 2 H 1 () + h 2 η 2 H 2 () + h 2 For T 0 h T 0 h + T M h η 2 L 2 () ( η 2 H 1 () + h 2γ η 2 H 1+γ () + h 2 η 2 L 2 ())) 1/2, h (0, h0). we have u H 2+k () and e.g. ) Anna-Margarete Sändig Graded Mesh Refinement 17/19
56 Main ideas of the proof For η = u I h u it holds ( ( e h DG C η 2 H 1 () + h 2 η 2 H 2 () + h 2 For T 0 h T 0 h + T M h η 2 L 2 () ( η 2 H 1 () + h 2γ η 2 H 1+γ () + h 2 η 2 L 2 ())) 1/2, h (0, h0). we have u H 2+k () and e.g. η 2 H 1 () Ch 2(k+1) = Ch 2(k+1) Ch 2(k+1) 2+k u 2 L 2 () r 2(β+1+k) r 2(β+1+k) u 2 V 2+k,2 (). β+1+k r 2(β+1+k) 2+k u 2 dx negative exponent ) Anna-Margarete Sändig Graded Mesh Refinement 17/19
57 Main ideas of the proof For η = u I h u it holds ( ( e h DG C η 2 H 1 () + h 2 η 2 H 2 () + h 2 For T 0 h T 0 h + T M h η 2 L 2 () ( η 2 H 1 () + h 2γ η 2 H 1+γ () + h 2 η 2 L 2 ())) 1/2, h (0, h0). we have u H 2+k () and e.g. η 2 H 1 () Ch 2(k+1) = Ch 2(k+1) Ch 2(k+1) 2+k u 2 L 2 () r 2(β+1+k) r 2(β+1+k) u 2 V 2+k,2 (). β+1+k Exploiting the grading h C 2hr 1 µ r 2(β+1+k) 2+k u 2 dx negative exponent we get h 2(k+1) r 2(β+1+k) Ch 2(k+1) r 2(1 µ)(k+1) 2(β+1+k) Ch 2(k+1) for µ β k+1 = H 0 ε k+1. Anna-Margarete Sändig Graded Mesh Refinement 17/19 )
58 For Th M we have u V 2,2 β+1 () H1+γ () for β = H 0 + ε and e.g. Anna-Margarete Sändig Graded Mesh Refinement 18/19
59 For Th M we have u V 2,2 β+1 () H1+γ () for β = H 0 + ε and e.g. u 2 H 1 () = r 2( β) r 2β u 2 dx r 2β u 2 dx positive exponent h 2( β) h 2( β) u 2 = V 2,2 h2γ β+1 () u 2 V 2,2 (). β+1 Anna-Margarete Sändig Graded Mesh Refinement 18/19
60 For Th M we have u V 2,2 β+1 () H1+γ () for β = H 0 + ε and e.g. u 2 H 1 () = r 2( β) r 2β u 2 dx r 2β u 2 dx positive exponent h 2( β) h 2( β) u 2 = V 2,2 h2γ β+1 () u 2 V 2,2 (). β+1 Using the inverse inequality we get I h u 2 H 1 () Ch 2 π hu L 2 () 2 h 2 u 2 L 2 () h 2( β) u 2 = V 2,2 h2γ β+1 () u 2 V 2,2 (). β+1 Anna-Margarete Sändig Graded Mesh Refinement 18/19
61 Happy birthday, dear Martin! Oberwolfach 2002 Anna-Margarete Sändig Graded Mesh Refinement 19/19
ANALYSIS OF THE FEM AND DGM FOR AN ELLIPTIC PROBLEM WITH A NONLINEAR NEWTON BOUNDARY CONDITION
Proceedings of EQUADIFF 2017 pp. 127 136 ANALYSIS OF THE FEM AND DGM FOR AN ELLIPTIC PROBLEM WITH A NONLINEAR NEWTON BOUNDARY CONDITION MILOSLAV FEISTAUER, ONDŘEJ BARTOŠ, FILIP ROSKOVEC, AND ANNA-MARGARETE
More informationBasic Concepts of Adaptive Finite Element Methods for Elliptic Boundary Value Problems
Basic Concepts of Adaptive Finite lement Methods for lliptic Boundary Value Problems Ronald H.W. Hoppe 1,2 1 Department of Mathematics, University of Houston 2 Institute of Mathematics, University of Augsburg
More informationSECOND ORDER TIME DISCONTINUOUS GALERKIN METHOD FOR NONLINEAR CONVECTION-DIFFUSION PROBLEMS
Proceedings of ALGORITMY 2009 pp. 1 10 SECOND ORDER TIME DISCONTINUOUS GALERKIN METHOD FOR NONLINEAR CONVECTION-DIFFUSION PROBLEMS MILOSLAV VLASÁK Abstract. We deal with a numerical solution of a scalar
More informationOn an Approximation Result for Piecewise Polynomial Functions. O. Karakashian
BULLETIN OF THE GREE MATHEMATICAL SOCIETY Volume 57, 010 (1 7) On an Approximation Result for Piecewise Polynomial Functions O. arakashian Abstract We provide a new approach for proving approximation results
More informationNumerical Solutions to Partial Differential Equations
Numerical Solutions to Partial Differential Equations Zhiping Li LMAM and School of Mathematical Sciences Peking University The Residual and Error of Finite Element Solutions Mixed BVP of Poisson Equation
More informationOptimal Error Estimates for the hp Version Interior Penalty Discontinuous Galerkin Finite Element Method
Report no. 03/06 Optimal Error Estimates for the hp Version Interior Penalty Discontinuous Galerkin Finite Element Method Emmanuil H. Georgoulis and Endre Süli Oxford University Computing Laboratory Numerical
More informationLECTURE 1: SOURCES OF ERRORS MATHEMATICAL TOOLS A PRIORI ERROR ESTIMATES. Sergey Korotov,
LECTURE 1: SOURCES OF ERRORS MATHEMATICAL TOOLS A PRIORI ERROR ESTIMATES Sergey Korotov, Institute of Mathematics Helsinki University of Technology, Finland Academy of Finland 1 Main Problem in Mathematical
More informationScientific Computing WS 2018/2019. Lecture 15. Jürgen Fuhrmann Lecture 15 Slide 1
Scientific Computing WS 2018/2019 Lecture 15 Jürgen Fuhrmann juergen.fuhrmann@wias-berlin.de Lecture 15 Slide 1 Lecture 15 Slide 2 Problems with strong formulation Writing the PDE with divergence and gradient
More informationVariational Formulations
Chapter 2 Variational Formulations In this chapter we will derive a variational (or weak) formulation of the elliptic boundary value problem (1.4). We will discuss all fundamental theoretical results that
More informationScientific Computing WS 2017/2018. Lecture 18. Jürgen Fuhrmann Lecture 18 Slide 1
Scientific Computing WS 2017/2018 Lecture 18 Jürgen Fuhrmann juergen.fuhrmann@wias-berlin.de Lecture 18 Slide 1 Lecture 18 Slide 2 Weak formulation of homogeneous Dirichlet problem Search u H0 1 (Ω) (here,
More informationProblems of Corner Singularities
Stuttgart 98 Problems of Corner Singularities Monique DAUGE Institut de Recherche MAthématique de Rennes Problems of Corner Singularities 1 Vertex and edge singularities For a polyhedral domain Ω and a
More informationNumerical Analysis of Higher Order Discontinuous Galerkin Finite Element Methods
Numerical Analysis of Higher Order Discontinuous Galerkin Finite Element Methods Contents Ralf Hartmann Institute of Aerodynamics and Flow Technology DLR (German Aerospace Center) Lilienthalplatz 7, 3808
More informationInstitut de Recherche MAthématique de Rennes
LMS Durham Symposium: Computational methods for wave propagation in direct scattering. - July, Durham, UK The hp version of the Weighted Regularization Method for Maxwell Equations Martin COSTABEL & Monique
More informationA posteriori error estimation for elliptic problems
A posteriori error estimation for elliptic problems Praveen. C praveen@math.tifrbng.res.in Tata Institute of Fundamental Research Center for Applicable Mathematics Bangalore 560065 http://math.tifrbng.res.in
More informationFinite Elements. Colin Cotter. January 15, Colin Cotter FEM
Finite Elements January 15, 2018 Why Can solve PDEs on complicated domains. Have flexibility to increase order of accuracy and match the numerics to the physics. has an elegant mathematical formulation
More informationFinite Elements. Colin Cotter. February 22, Colin Cotter FEM
Finite Elements February 22, 2019 In the previous sections, we introduced the concept of finite element spaces, which contain certain functions defined on a domain. Finite element spaces are examples of
More informationLECTURE # 0 BASIC NOTATIONS AND CONCEPTS IN THE THEORY OF PARTIAL DIFFERENTIAL EQUATIONS (PDES)
LECTURE # 0 BASIC NOTATIONS AND CONCEPTS IN THE THEORY OF PARTIAL DIFFERENTIAL EQUATIONS (PDES) RAYTCHO LAZAROV 1 Notations and Basic Functional Spaces Scalar function in R d, d 1 will be denoted by u,
More informationProjected Surface Finite Elements for Elliptic Equations
Available at http://pvamu.edu/aam Appl. Appl. Math. IN: 1932-9466 Vol. 8, Issue 1 (June 2013), pp. 16 33 Applications and Applied Mathematics: An International Journal (AAM) Projected urface Finite Elements
More informationLaplace s Equation. Chapter Mean Value Formulas
Chapter 1 Laplace s Equation Let be an open set in R n. A function u C 2 () is called harmonic in if it satisfies Laplace s equation n (1.1) u := D ii u = 0 in. i=1 A function u C 2 () is called subharmonic
More informationChapter 6 A posteriori error estimates for finite element approximations 6.1 Introduction
Chapter 6 A posteriori error estimates for finite element approximations 6.1 Introduction The a posteriori error estimation of finite element approximations of elliptic boundary value problems has reached
More informationDifferent Approaches to a Posteriori Error Analysis of the Discontinuous Galerkin Method
WDS'10 Proceedings of Contributed Papers, Part I, 151 156, 2010. ISBN 978-80-7378-139-2 MATFYZPRESS Different Approaces to a Posteriori Error Analysis of te Discontinuous Galerkin Metod I. Šebestová Carles
More informationarxiv: v1 [math.na] 29 Feb 2016
EFFECTIVE IMPLEMENTATION OF THE WEAK GALERKIN FINITE ELEMENT METHODS FOR THE BIHARMONIC EQUATION LIN MU, JUNPING WANG, AND XIU YE Abstract. arxiv:1602.08817v1 [math.na] 29 Feb 2016 The weak Galerkin (WG)
More information[2] (a) Develop and describe the piecewise linear Galerkin finite element approximation of,
269 C, Vese Practice problems [1] Write the differential equation u + u = f(x, y), (x, y) Ω u = 1 (x, y) Ω 1 n + u = x (x, y) Ω 2, Ω = {(x, y) x 2 + y 2 < 1}, Ω 1 = {(x, y) x 2 + y 2 = 1, x 0}, Ω 2 = {(x,
More informationAn A Posteriori Error Estimate for Discontinuous Galerkin Methods
An A Posteriori Error Estimate for Discontinuous Galerkin Methods Mats G Larson mgl@math.chalmers.se Chalmers Finite Element Center Mats G Larson Chalmers Finite Element Center p.1 Outline We present an
More informationDiscontinuous Galerkin Methods: Theory, Computation and Applications
Discontinuous Galerkin Methods: Theory, Computation and Applications Paola. Antonietti MOX, Dipartimento di Matematica Politecnico di Milano.MO. X MODELLISTICA E CALCOLO SCIENTIICO. MODELING AND SCIENTIIC
More informationDiscontinuous Galerkin Methods: An Overview and Some Applications. Daya Reddy UNIVERSITY OF CAPE TOWN
Discontinuous Galerkin Methods: An Overview and Some Applications Daya Reddy UNIVRSITY OF CAP TOWN Joint work with Beverley Grieshaber and Andrew McBride SANUM, Stellenbosch, 22 24 March 2016 Structure
More informationStandard Finite Elements and Weighted Regularization
Standard Finite Elements and Weighted Regularization A Rehabilitation Martin COSTABEL & Monique DAUGE Institut de Recherche MAthématique de Rennes http://www.maths.univ-rennes1.fr/~dauge Slides of the
More informationINTRODUCTION TO FINITE ELEMENT METHODS
INTRODUCTION TO FINITE ELEMENT METHODS LONG CHEN Finite element methods are based on the variational formulation of partial differential equations which only need to compute the gradient of a function.
More informationNumerical methods for PDEs FEM convergence, error estimates, piecewise polynomials
Platzhalter für Bild, Bild auf Titelfolie hinter das Logo einsetzen Numerical methods for PDEs FEM convergence, error estimates, piecewise polynomials Dr. Noemi Friedman Contents of the course Fundamentals
More informationPREPRINT 2010:25. Fictitious domain finite element methods using cut elements: II. A stabilized Nitsche method ERIK BURMAN PETER HANSBO
PREPRINT 2010:25 Fictitious domain finite element methods using cut elements: II. A stabilized Nitsche method ERIK BURMAN PETER HANSBO Department of Mathematical Sciences Division of Mathematics CHALMERS
More informationEnergy norm a-posteriori error estimation for divergence-free discontinuous Galerkin approximations of the Navier-Stokes equations
INTRNATIONAL JOURNAL FOR NUMRICAL MTHODS IN FLUIDS Int. J. Numer. Meth. Fluids 19007; 1:1 [Version: 00/09/18 v1.01] nergy norm a-posteriori error estimation for divergence-free discontinuous Galerkin approximations
More informationAbstract. 1. Introduction
Journal of Computational Mathematics Vol.28, No.2, 2010, 273 288. http://www.global-sci.org/jcm doi:10.4208/jcm.2009.10-m2870 UNIFORM SUPERCONVERGENCE OF GALERKIN METHODS FOR SINGULARLY PERTURBED PROBLEMS
More informationA Finite Element Method Using Singular Functions for Poisson Equations: Mixed Boundary Conditions
A Finite Element Method Using Singular Functions for Poisson Equations: Mixed Boundary Conditions Zhiqiang Cai Seokchan Kim Sangdong Kim Sooryun Kong Abstract In [7], we proposed a new finite element method
More informationFrom Completing the Squares and Orthogonal Projection to Finite Element Methods
From Completing the Squares and Orthogonal Projection to Finite Element Methods Mo MU Background In scientific computing, it is important to start with an appropriate model in order to design effective
More informationhp-version Discontinuous Galerkin Finite Element Methods for Semilinear Parabolic Problems
Report no. 3/11 hp-version Discontinuous Galerkin Finite Element Methods for Semilinear Parabolic Problems Andris Lasis Endre Süli We consider the hp version interior penalty discontinuous Galerkin finite
More informationThe Mortar Boundary Element Method
The Mortar Boundary Element Method A Thesis submitted for the degree of Doctor of Philosophy by Martin Healey School of Information Systems, Computing and Mathematics Brunel University March 2010 Abstract
More informationNumerical Solutions to Partial Differential Equations
Numerical Solutions to Partial Differential Equations Zhiping Li LMAM and School of Mathematical Sciences Peking University Nonconformity and the Consistency Error First Strang Lemma Abstract Error Estimate
More informationMultigrid Methods for Maxwell s Equations
Multigrid Methods for Maxwell s Equations Jintao Cui Institute for Mathematics and Its Applications University of Minnesota Outline Nonconforming Finite Element Methods for a Two Dimensional Curl-Curl
More informationOn the relationship of local projection stabilization to other stabilized methods for one-dimensional advection-diffusion equations
On the relationship of local projection stabilization to other stabilized methods for one-dimensional advection-diffusion equations Lutz Tobiska Institut für Analysis und Numerik Otto-von-Guericke-Universität
More informationANALYSIS OF THE FINITE ELEMENT METHOD FOR TRANSMISSION/MIXED BOUNDARY VALUE PROBLEMS ON GENERAL POLYGONAL DOMAINS
ANALYSIS OF THE FINITE ELEMENT METHOD FOR TRANSMISSION/MIXED BOUNDARY VALUE PROBLEMS ON GENERAL POLYGONAL DOMAINS HENGGUANG LI, ANNA MAZZUCATO, AND VICTOR NISTOR Abstract. We study theoretical and practical
More informationSobolev Spaces 27 PART II. Review of Sobolev Spaces
Sobolev Spaces 27 PART II Review of Sobolev Spaces Sobolev Spaces 28 SOBOLEV SPACES WEAK DERIVATIVES I Given R d, define a multi index α as an ordered collection of integers α = (α 1,...,α d ), such that
More informationMULTIGRID METHODS FOR MAXWELL S EQUATIONS
MULTIGRID METHODS FOR MAXWELL S EQUATIONS A Dissertation Submitted to the Graduate Faculty of the Louisiana State University and Agricultural and Mechanical College in partial fulfillment of the requirements
More informationNumerical methods for PDEs FEM convergence, error estimates, piecewise polynomials
Platzhalter für Bild, Bild auf Titelfolie hinter das Logo einsetzen Numerical methods for PDEs FEM convergence, error estimates, piecewise polynomials Dr. Noemi Friedman Contents of the course Fundamentals
More informationAdaptive Finite Element Methods Lecture 1: A Posteriori Error Estimation
Adaptive Finite Element Methods Lecture 1: A Posteriori Error Estimation Department of Mathematics and Institute for Physical Science and Technology University of Maryland, USA www.math.umd.edu/ rhn 7th
More informationR T (u H )v + (2.1) J S (u H )v v V, T (2.2) (2.3) H S J S (u H ) 2 L 2 (S). S T
2 R.H. NOCHETTO 2. Lecture 2. Adaptivity I: Design and Convergence of AFEM tarting with a conforming mesh T H, the adaptive procedure AFEM consists of loops of the form OLVE ETIMATE MARK REFINE to produce
More informationThomas Apel 1, Ariel L. Lombardi 2 and Max Winkler 1
Mathematical Modelling and Numerical Analysis Modélisation Mathématique et Analyse Numérique Will be set by the publisher ANISOTROPIC MESH REFINEMENT IN POLYHEDRAL DOMAINS: ERROR ESTIMATES WITH DATA IN
More informationThe hp-version of the boundary element method with quasi-uniform meshes in three dimensions
The hp-version of the boundary element method with quasi-uniform meshes in three dimensions Alexei Bespalov Norbert Heuer Dedicated to Professor Ernst P. Stephan on the occasion of his 60th birthday. Abstract
More informationA posteriori error estimation of approximate boundary fluxes
COMMUNICATIONS IN NUMERICAL METHODS IN ENGINEERING Commun. Numer. Meth. Engng 2008; 24:421 434 Published online 24 May 2007 in Wiley InterScience (www.interscience.wiley.com)..1014 A posteriori error estimation
More informationhp-dgfem FOR SECOND-ORDER MIXED ELLIPTIC PROBLEMS IN POLYHEDRA
MATHEMATICS OF COMPUTATION Volume 00, Number 0, Pages 000 000 S 0025-5718(XX)0000-0 hp-dgfem FOR SECOND-ORDER MIXED ELLIPTIC PROBLEMS IN POLYHEDRA DOMINIK SCHÖTZAU, CHRISTOPH SCHWAB, AND THOMAS P. WIHLER
More informationThree remarks on anisotropic finite elements
Three remarks on anisotropic finite elements Thomas Apel Universität der Bundeswehr München Workshop Numerical Analysis for Singularly Perturbed Problems dedicated to the 60th birthday of Martin Stynes
More information1. Introduction. We consider the model problem that seeks an unknown function u = u(x) satisfying
A SIMPLE FINITE ELEMENT METHOD FOR LINEAR HYPERBOLIC PROBLEMS LIN MU AND XIU YE Abstract. In this paper, we introduce a simple finite element method for solving first order hyperbolic equations with easy
More informationRESIDUAL BASED ERROR ESTIMATES FOR THE SPACE-TIME DISCONTINUOUS GALERKIN METHOD APPLIED TO NONLINEAR HYPERBOLIC EQUATIONS
Proceedings of ALGORITMY 2016 pp. 113 124 RESIDUAL BASED ERROR ESTIMATES FOR THE SPACE-TIME DISCONTINUOUS GALERKIN METHOD APPLIED TO NONLINEAR HYPERBOLIC EQUATIONS VÍT DOLEJŠÍ AND FILIP ROSKOVEC Abstract.
More informationPoint estimates for Green s matrix to boundary value problems for second order elliptic systems in a polyhedral cone
Maz ya, V. G., Roßmann, J.: Estimates for Green s matrix 1 ZAMM Z. angew. Math. Mech. 00 2004 0, 1 30 Maz ya, V. G.; Roßmann, J. Point estimates for Green s matrix to boundary value problems for second
More informationChapter 5 A priori error estimates for nonconforming finite element approximations 5.1 Strang s first lemma
Chapter 5 A priori error estimates for nonconforming finite element approximations 51 Strang s first lemma We consider the variational equation (51 a(u, v = l(v, v V H 1 (Ω, and assume that the conditions
More informationWeighted Regularization of Maxwell Equations Computations in Curvilinear Polygons
Weighted Regularization of Maxwell Equations Computations in Curvilinear Polygons Martin Costabel, Monique Dauge, Daniel Martin and Gregory Vial IRMAR, Université de Rennes, Campus de Beaulieu, Rennes,
More informationSecond Order Elliptic PDE
Second Order Elliptic PDE T. Muthukumar tmk@iitk.ac.in December 16, 2014 Contents 1 A Quick Introduction to PDE 1 2 Classification of Second Order PDE 3 3 Linear Second Order Elliptic Operators 4 4 Periodic
More informationETNA Kent State University
Electronic Transactions on Numerical Analysis. Volume 37, pp. 41-69, 2010. Copyright 2010,. ISSN 1068-9613. ETNA ANALYSIS OF THE FINITE ELEMENT METHOD FOR TRANSMISSION/MIXED BOUNDARY VALUE PROBLEMS ON
More informationACM/CMS 107 Linear Analysis & Applications Fall 2017 Assignment 2: PDEs and Finite Element Methods Due: 7th November 2017
ACM/CMS 17 Linear Analysis & Applications Fall 217 Assignment 2: PDEs and Finite Element Methods Due: 7th November 217 For this assignment the following MATLAB code will be required: Introduction http://wwwmdunloporg/cms17/assignment2zip
More informationThe Discontinuous Galerkin Finite Element Method
The Discontinuous Galerkin Finite Element Method Michael A. Saum msaum@math.utk.edu Department of Mathematics University of Tennessee, Knoxville The Discontinuous Galerkin Finite Element Method p.1/41
More informationBoundary Value Problems and Iterative Methods for Linear Systems
Boundary Value Problems and Iterative Methods for Linear Systems 1. Equilibrium Problems 1.1. Abstract setting We want to find a displacement u V. Here V is a complete vector space with a norm v V. In
More informationSimple Examples on Rectangular Domains
84 Chapter 5 Simple Examples on Rectangular Domains In this chapter we consider simple elliptic boundary value problems in rectangular domains in R 2 or R 3 ; our prototype example is the Poisson equation
More informationMaximum norm estimates for energy-corrected finite element method
Maximum norm estimates for energy-corrected finite element method Piotr Swierczynski 1 and Barbara Wohlmuth 1 Technical University of Munich, Institute for Numerical Mathematics, piotr.swierczynski@ma.tum.de,
More informationIterative Methods for Linear Systems
Iterative Methods for Linear Systems 1. Introduction: Direct solvers versus iterative solvers In many applications we have to solve a linear system Ax = b with A R n n and b R n given. If n is large the
More informationPreconditioned space-time boundary element methods for the heat equation
W I S S E N T E C H N I K L E I D E N S C H A F T Preconditioned space-time boundary element methods for the heat equation S. Dohr and O. Steinbach Institut für Numerische Mathematik Space-Time Methods
More informationPRECONDITIONING OF DISCONTINUOUS GALERKIN METHODS FOR SECOND ORDER ELLIPTIC PROBLEMS. A Dissertation VESELIN ASENOV DOBREV
PRECONDITIONING OF DISCONTINUOUS GALERKIN METHODS FOR SECOND ORDER ELLIPTIC PROBLEMS A Dissertation by VESELIN ASENOV DOBREV Submitted to the Office of Graduate Studies of Texas A&M University in partial
More informationc 2005 Society for Industrial and Applied Mathematics
SIAM J NUMER ANAL Vol 42, No 5, pp 1932 1958 c 2005 Society for Industrial and Applied Mathematics ERROR ESTIMATES FOR A FINITE VOLUME ELEMENT METHOD FOR ELLIPTIC PDES IN NONCONVEX POLYGONAL DOMAINS P
More informationA Finite Element Method Using Singular Functions: Interface Problems
A Finite Element Method Using Singular Functions: Interface Problems Seokchan Kim Zhiqiang Cai Jae-Hong Pyo Sooryoun Kong Abstract The solution of the interface problem is only in H 1+α (Ω) with α > 0
More informationKey words. Incompressible magnetohydrodynamics, mixed finite element methods, discontinuous Galerkin methods
A MIXED DG METHOD FOR LINEARIZED INCOMPRESSIBLE MAGNETOHYDRODYNAMICS PAUL HOUSTON, DOMINIK SCHÖTZAU, AND XIAOXI WEI Journal of Scientific Computing, vol. 40, pp. 8 34, 009 Abstract. We introduce and analyze
More informationWeak Galerkin Finite Element Scheme and Its Applications
Weak Galerkin Finite Element Scheme and Its Applications Ran Zhang Department of Mathematics Jilin University, China IMS, Singapore February 6, 2015 Talk Outline Motivation WG FEMs: Weak Operators + Stabilizer
More informationQUASI-OPTIMAL RATES OF CONVERGENCE FOR THE GENERALIZED FINITE ELEMENT METHOD IN POLYGONAL DOMAINS. Anna L. Mazzucato, Victor Nistor, and Qingqin Qu
QUASI-OPTIMAL RATES OF CONVERGENCE FOR THE GENERALIZED FINITE ELEMENT METHOD IN POLYGONAL DOMAINS By Anna L. Mazzucato, Victor Nistor, and Qingqin Qu IMA Preprint Series #2408 (September 2012) INSTITUTE
More informationMORTAR MULTISCALE FINITE ELEMENT METHODS FOR STOKES-DARCY FLOWS
MORTAR MULTISCALE FINITE ELEMENT METHODS FOR STOKES-DARCY FLOWS VIVETTE GIRAULT, DANAIL VASSILEV, AND IVAN YOTOV Abstract. We investigate mortar multiscale numerical methods for coupled Stokes and Darcy
More informationON SOME ELLIPTIC PROBLEMS IN UNBOUNDED DOMAINS
Chin. Ann. Math.??B(?), 200?, 1 20 DOI: 10.1007/s11401-007-0001-x ON SOME ELLIPTIC PROBLEMS IN UNBOUNDED DOMAINS Michel CHIPOT Abstract We present a method allowing to obtain existence of a solution for
More informationA space-time Trefftz method for the second order wave equation
A space-time Trefftz method for the second order wave equation Lehel Banjai The Maxwell Institute for Mathematical Sciences Heriot-Watt University, Edinburgh Rome, 10th Apr 2017 Joint work with: Emmanuil
More informationIsogeometric Analysis:
Isogeometric Analysis: some approximation estimates for NURBS L. Beirao da Veiga, A. Buffa, Judith Rivas, G. Sangalli Euskadi-Kyushu 2011 Workshop on Applied Mathematics BCAM, March t0th, 2011 Outline
More informationweak Galerkin, finite element methods, interior estimates, second-order elliptic
INERIOR ENERGY ERROR ESIMAES FOR HE WEAK GALERKIN FINIE ELEMEN MEHOD HENGGUANG LI, LIN MU, AND XIU YE Abstract Consider the Poisson equation in a polytopal domain Ω R d (d = 2, 3) as the model problem
More informationAn Equal-order DG Method for the Incompressible Navier-Stokes Equations
An Equal-order DG Method for the Incompressible Navier-Stokes Equations Bernardo Cockburn Guido anschat Dominik Schötzau Journal of Scientific Computing, vol. 40, pp. 188 10, 009 Abstract We introduce
More information1. Let a(x) > 0, and assume that u and u h are the solutions of the Dirichlet problem:
Mathematics Chalmers & GU TMA37/MMG800: Partial Differential Equations, 011 08 4; kl 8.30-13.30. Telephone: Ida Säfström: 0703-088304 Calculators, formula notes and other subject related material are not
More informationi=1 α i. Given an m-times continuously
1 Fundamentals 1.1 Classification and characteristics Let Ω R d, d N, d 2, be an open set and α = (α 1,, α d ) T N d 0, N 0 := N {0}, a multiindex with α := d i=1 α i. Given an m-times continuously differentiable
More informationFinite Element Methods for Fourth Order Variational Inequalities
Louisiana State University LSU Digital Commons LSU Doctoral Dissertations Graduate School 2013 Finite Element Methods for Fourth Order Variational Inequalities Yi Zhang Louisiana State University and Agricultural
More informationSingularly Perturbed Partial Differential Equations
WDS'9 Proceedings of Contributed Papers, Part I, 54 59, 29. ISN 978-8-7378--9 MTFYZPRESS Singularly Perturbed Partial Differential Equations J. Lamač Charles University, Faculty of Mathematics and Physics,
More informationInvertibility of the biharmonic single layer potential operator
Invertibility of the biharmonic single layer potential operator Martin COSTABEL & Monique DAUGE Abstract. The 2 2 system of integral equations corresponding to the biharmonic single layer potential in
More informationTraces, extensions and co-normal derivatives for elliptic systems on Lipschitz domains
Traces, extensions and co-normal derivatives for elliptic systems on Lipschitz domains Sergey E. Mikhailov Brunel University West London, Department of Mathematics, Uxbridge, UB8 3PH, UK J. Math. Analysis
More informationA very short introduction to the Finite Element Method
A very short introduction to the Finite Element Method Till Mathis Wagner Technical University of Munich JASS 2004, St Petersburg May 4, 2004 1 Introduction This is a short introduction to the finite element
More informationA space-time Trefftz method for the second order wave equation
A space-time Trefftz method for the second order wave equation Lehel Banjai The Maxwell Institute for Mathematical Sciences Heriot-Watt University, Edinburgh & Department of Mathematics, University of
More informationTheory of PDE Homework 2
Theory of PDE Homework 2 Adrienne Sands April 18, 2017 In the following exercises we assume the coefficients of the various PDE are smooth and satisfy the uniform ellipticity condition. R n is always an
More information1. The COMPLEX PLANE AND ELEMENTARY FUNCTIONS: Complex numbers; stereographic projection; simple and multiple connectivity, elementary functions.
Complex Analysis Qualifying Examination 1 The COMPLEX PLANE AND ELEMENTARY FUNCTIONS: Complex numbers; stereographic projection; simple and multiple connectivity, elementary functions 2 ANALYTIC FUNCTIONS:
More informationTwo-Scale Composite Finite Element Method for Dirichlet Problems on Complicated Domains
Numerische Mathematik manuscript No. will be inserted by the editor) Two-Scale Composite Finite Element Method for Dirichlet Problems on Complicated Domains M. Rech, S. Sauter, A. Smolianski Institut für
More informationFinite Element Error Estimates in Non-Energy Norms for the Two-Dimensional Scalar Signorini Problem
Journal manuscript No. (will be inserted by the editor Finite Element Error Estimates in Non-Energy Norms for the Two-Dimensional Scalar Signorini Problem Constantin Christof Christof Haubner Received:
More informationASYMPTOTICALLY EXACT A POSTERIORI ESTIMATORS FOR THE POINTWISE GRADIENT ERROR ON EACH ELEMENT IN IRREGULAR MESHES. PART II: THE PIECEWISE LINEAR CASE
MATEMATICS OF COMPUTATION Volume 73, Number 246, Pages 517 523 S 0025-5718(0301570-9 Article electronically published on June 17, 2003 ASYMPTOTICALLY EXACT A POSTERIORI ESTIMATORS FOR TE POINTWISE GRADIENT
More informationBasic Principles of Weak Galerkin Finite Element Methods for PDEs
Basic Principles of Weak Galerkin Finite Element Methods for PDEs Junping Wang Computational Mathematics Division of Mathematical Sciences National Science Foundation Arlington, VA 22230 Polytopal Element
More informationPIECEWISE POLYNOMIAL INTERPOLATION IN MUCKENHOUPT WEIGHTED SOBOLEV SPACES AND APPLICATIONS
PIECEWISE POLYNOMIAL INTERPOLATION IN MUCKENHOUPT WEIGHTED SOBOLEV SPACES AND APPLICATIONS RICARDO H. NOCHETTO, ENRIQUE OTÁROLA, AND ABNER J. SALGADO Abstract. We develop a constructive piecewise polynomial
More informationApplied/Numerical Analysis Qualifying Exam
Applied/Numerical Analysis Qualifying Exam August 9, 212 Cover Sheet Applied Analysis Part Policy on misprints: The qualifying exam committee tries to proofread exams as carefully as possible. Nevertheless,
More informationHybridized Discontinuous Galerkin Methods
Hybridized Discontinuous Galerkin Methods Theory and Christian Waluga Joint work with Herbert Egger (Uni Graz) 1st DUNE User Meeting, Stuttgart Christian Waluga (AICES) HDG Methods October 6-8, 2010 1
More informationANALYSIS OF A MODIFIED SCHRÖDINGER OPERATOR IN 2D: REGULARITY, INDEX, AND FEM
ANALYSIS OF A MODIFIED SCHRÖDINGER OPERATOR IN 2D: REGULARITY, INDEX, AND FEM HENGGUANG LI AND VICTOR NISTOR Version: 2.; Revised: April 2 by V.; Run: January 4, 2008 Abstract. Let r = (x 2 +x2 2 )/2 be
More informationIt is known that Morley element is not C 0 element and it is divergent for Poisson equation (see [6]). When Morley element is applied to solve problem
Modied Morley Element Method for a ourth Order Elliptic Singular Perturbation Problem Λ Wang Ming LMAM, School of Mathematical Science, Peking University Jinchao u School of Mathematical Science, Peking
More informationA BIVARIATE SPLINE METHOD FOR SECOND ORDER ELLIPTIC EQUATIONS IN NON-DIVERGENCE FORM
A BIVARIAE SPLINE MEHOD FOR SECOND ORDER ELLIPIC EQUAIONS IN NON-DIVERGENCE FORM MING-JUN LAI AND CHUNMEI WANG Abstract. A bivariate spline method is developed to numerically solve second order elliptic
More informationChapter 3 Conforming Finite Element Methods 3.1 Foundations Ritz-Galerkin Method
Chapter 3 Conforming Finite Element Methods 3.1 Foundations 3.1.1 Ritz-Galerkin Method Let V be a Hilbert space, a(, ) : V V lr a bounded, V-elliptic bilinear form and l : V lr a bounded linear functional.
More informationSpace-time sparse discretization of linear parabolic equations
Space-time sparse discretization of linear parabolic equations Roman Andreev August 2, 200 Seminar for Applied Mathematics, ETH Zürich, Switzerland Support by SNF Grant No. PDFMP2-27034/ Part of PhD thesis
More informationDifferential Equations Preliminary Examination
Differential Equations Preliminary Examination Department of Mathematics University of Utah Salt Lake City, Utah 84112 August 2007 Instructions This examination consists of two parts, called Part A and
More informationA Multigrid Method for Two Dimensional Maxwell Interface Problems
A Multigrid Method for Two Dimensional Maxwell Interface Problems Susanne C. Brenner Department of Mathematics and Center for Computation & Technology Louisiana State University USA JSA 2013 Outline A
More information