Analysis of Dynamical Systems

Transcription

1 2 YFX1520 Nonlinear phase portrait Mathematical Modelling and Nonlinear Dynamics Coursework Assignments 1 ϕ (t) ϕ(t) Dmitri Kartofelev, PhD 2018

2 Variant 1 Part 1: Liénard type equation ẍ + µ(x 2 1)ẋ + tanh(x) = 0, where µ is the constants and it can be shown that for µ > 0 only one periodic solution exists. Part 2: Rössler attractor 1 ẋ = y z, ẏ = x + ay, ż = b + z (x c), where a, b ja c are constants. Parameter version 1.1 version 1.2 a b c Some aspects of the dynamics of this system are discussed during the lectures. D. Kartofelev 1 Variant 1

3 Variant 2 Part 1: Bacterial respiration by Fairén and Velarde where constants A, B and Q are positive. Part 2: Lorenz attractor 1 ẋ = B x xy 1 + Qx, 2 ẏ = A xy 1 + Qx, 2 Parameter version 2.1 version 2.2 A B Q ẋ = σ (y x), ẏ = rx y xz, ż = xy bz, where σ, r, and b are constants. Parameter value σ 10 b 8/3 r 28 1 Some aspects of the dynamics of this system are discussed during the lectures. D. Kartofelev 2 Variant 2

4 Variant 3 Part 1: Brusselator { ẋ = a x bx + x 2 y, where a and b > 0 are constants. ẏ = bx x 2 y, Part 2: Newton Leipnik chaotic system Parameter version 3.1 version 3.2 a b ẋ = ax + y + 10yz, ẏ = x 0.4y + 5xz, ż = bz 5xy, where a, b > 0 and a = 0.4 and b = D. Kartofelev 3 Variant 3

5 Variant 4 Part 1: Ueda oscillator where k, B, and ω are constants. ẍ + kẋ + x 3 = B cos(ωt), Parameter version 4.1 version 4.2 k B ω Part 2: Thomas cyclically symmetric attractor ẋ = sin(y) bx, ẏ = sin(z) by, ż = sin(x) bz, where b is a constant and corresponds to how dissipative the system is, and acts as a bifurcation parameter. Select b < and b 0. D. Kartofelev 4 Variant 4

6 Variant 5 Part 1: Duffing oscillator 1 where α, β, δ, ω, and f are constants. Part 2: Sprott A, chaotic flow ẍ + δẋ βx + αx 3 = f cos(ωt), Parameter value α 100 β 1 δ 1 ω f 2.4 ẋ = y, ẏ = x + yz, ż = 1 y 2. 1 Some aspects of the dynamics of this system are discussed during the lectures. D. Kartofelev 5 Variant 5

7 Variant 6 Part 1: Chemical reaction (chlorine dioxide iodine malonic acid reaction) where a and b are constants. Part 2: Lorenz-84 model ẋ = a x 4xy 1 + x, ( 2 ẏ = bx 1 y ), 1 + x 2 Parameter version 6.1 version 6.2 a b 4 2 ẋ = y 2 z 2 ax + af, ẏ = xy bxz y + G, ż = bxy + xz z, where a, b, F and G are constants. Parameter value a 0.25 b 4.0 F 8.0 G 1.0 D. Kartofelev 6 Variant 6

8 Variant 7 Part 1: Glycolysis 1 { ẋ = x + ay + x 2 y, where a and b are constants. Part 2: Simplest dissipative flow ẏ = b ay x 2 y, Parameter value a 0.08 b 0.6 where constant A = x + Aẍ ẋ 2 + x = 0, 1 Some aspects of the dynamics of this system are discussed during the lectures. D. Kartofelev 7 Variant 7

9 Variant 8 Part 1: Van der Pol oscillator 1 where b is a constants. ẍ b (1 x 2 ) ẋ + x = 0, Part 2: Sprott B, chaotic flow Parameter version 8.1 version 8.2 b 5 1 ẋ = yz, ẏ = x y, ż = 1 xy. 1 Some aspects of the dynamics of this system are discussed during the lectures. D. Kartofelev 8 Variant 8

10 Variant 9 Part 1: Forced Van der Pol oscillator where b, f, and ω are constants. Part 2: Sprott C, chaotic flow ẍ b (1 x 2 ) ẋ + x = f cos(ωt), Parameter version 9.1 version 9.2 b 5 1 f 4 2 ω ẋ = yz, ẏ = x y, ż = 1 x 2. D. Kartofelev 9 Variant 9

11 Variant 10 Part 1: Morse equation where α, β, f, and ω are constants. Part 2: Sprott E, chaotic flow ẍ + αẋ + β (1 e x ) e x = f cos(ωt), Parameter value α 0.8 β 8 f 2.5 ω ẋ = yz, ẏ = x 2 y, ż = 1 4x. D. Kartofelev 10 Variant 10

12 Variant 11 Part 1: Nerve impulse action potential (Bonhoeffer-Van der Pol) where a, b, c, f, and ω are constants. Part 2: Sprott G, chaotic flow ẋ = x x3 3 y + f cos(ωt), ẏ = c (x + a by), Parameter value a 0.7 b 0.8 c 0.1 f 0.6 ω 1 ẋ = 0.4 x + z, ẏ = xz y, ż = x + y. D. Kartofelev 11 Variant 11

13 Variant 12 Part 1: Lotka-Volterra equations (predator prey model) { ẋ = ax xy, where a and b are constants. Part 2: Sprott I, chaotic flow ẏ = xy by, Parameter value a 2 b 1 ẋ = 0.2 y, ẏ = x + z, ż = x + y 2 z. D. Kartofelev 12 Variant 12

14 Variant 13 Part 1: Duffing-Van der Pol oscillator where α, β ω 0, ω, and f are constants. Part 2: Sprott K, chaotic flow ẍ α (1 x 2 ) ẋ ω 2 0x + βx 3 = f cos(ωt), Parameter version 13.1 version 13.1 α β ω f ω ẋ = xy z, ẏ = x y, ż = x z. D. Kartofelev 13 Variant 13

15 Variant 14 Part 1: Velocity dependent forced oscillation where λ, α, ω 0, ω, and f are constants. Part 2: Sprott M, chaotic flow (1 + λx 2 ) ẍ λxẋ 2 + αẋ + ω 2 0x = f sin(ωt), Parameter version 14.1 version 14.2 λ α ω f ω ẋ = z, ẏ = x 2 y, ż = x + y. D. Kartofelev 14 Variant 14

16 Variant 15 Part 1: Particle in a double well potential with linear damping ẍ + γ ẋ 1 2 (1 x2 ) x = 0, where γ is the coefficient of damping and γ = 0.1. Part 2: Modified Chen attractor ẋ = a(y x), ẏ = (c a)x xz + cy + m, ż = xy bz, where the constants have values a = 35, b = 3, c = 28, m = D. Kartofelev 15 Variant 15

17 Variant 16 Part 1: Bonhoeffer-Van der Pol oscillator where A 0, a, b, and c are constants. Part 2: Sprott O, chaotic flow ẋ = x x3 3 y + A 0, ẏ = c (x + a by), ẋ = y, ẏ = x z, ż = x + xz y. D. Kartofelev 16 Variant 16

18 Variant 17 Part 1: Nameless system #1 Analyse 2-D system { ẋ = (x + 2) 2x arctan(y 2), ẏ = sin(x + 2) + e 3y 6 1, where the fixed point is (x, y ) = ( 2, 2). Part 2: Sprott Q, chaotic flow ẋ = z, ẏ = x y, ż = 3.1 x + y z. D. Kartofelev 17 Variant 17

19 Variant 18 Part 1: Nameless system #2 Analyse 2-D system where the fixed point is (x, y ) = ( 1, 4). Part 2: Sprott S, chaotic flow ẋ = (x + 1) 2 cos(2x) 4 ln(y 3), (y 4)2 ẏ = sin(x + 1) + 2 y + 1, ẋ = x 4 y, ẏ = x + z 2, ż = 1 + x. D. Kartofelev 18 Variant 18

20 Variant 19 Part 1: Nameless system #3 Analyse 2-D system { ẋ = x sin(3(x 1)) (y 1) 2 tan(y) 1, ẏ = 2 sin 2 (x 1) + y 2 y 6, where the fixed point is (x, y ) = (1, 1). Part 2: Sprott H, chaotic flow ẋ = y + z 2, ẏ = x y, ż = x z. D. Kartofelev 19 Variant 19

21 Variant 20 Part 1: Liénard equation where µ is a constant. ẍ (µ x 2 ) ẋ + x = 0, Parameter version 20.1 version 20.2 µ Part 2: Chen attractor ẋ = a(y x), ẏ = (c a)x xz + cy, ż = xy bz, where the constants have values a = 35, b = 3, c = 28. D. Kartofelev 20 Variant 20

22 Variant 21 Part 1: Nameless system #4 { ẋ = x y + x(x 2 + 2y 2 ), Part 2: Sprott L, chaotic flow ẏ = x y + y(x 2 + 2y 2 ). ẋ = y + 3.9z, ẏ = 0.9x 2 y, ż = 1 x. D. Kartofelev 21 Variant 21