TURBULENCE MODELING FOR POLYMER SOLUTIONS

Transcription

1 TURBULENCE MODELING FOR POLYMER SOLUTIONS Fernando T. Pinho 1 Mohammadali Masoudian 1 Carlos B. da Silva 2 1 Transport Phenomena Research Center (CEFT), Mechanical Engineering Department, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias s/n, Porto, Portugal 2 IDMEC/IST, Department of Mechanical Engineering, Instituto Superior Técnico, University of Lisbon, Avenida Rovisco Pais, , Lisbon, Portugal webpage: fpinho@fe.up.pt mmasoudian@fe.up.pt carlos.silva@ist.utl.pt Flowing Matter 2016 Porto Cost Action MP1305 January 11-15, 2016

2 WHAT HAPPENS WHEN YOU ADD POLYMER TO A SOLVENT Tom s data Flow rate versus polymer concentration at different -dp/dx for solutions of polymethyl methacrylate in monochlorobenzene (Toms, 1949) Tanner & Walters, Rheology: An Historical Perspective (1998) Elsevier Flowing Matter

3 APPLICATIONS AND MOTIVATION Drilling for oil and gas Drilling muds contain polymers and other additives. Control of pressure variation is absolutely essential for safe operation Transport of oil in pipelines Frequent, used essentially in maintenance (polymer degradation). District heating and cooling systems Surfactants (wormlike micelles (do not degrade)): Very effective and successful, but requires more extensive use and control over environmental spills. Design of efficient systems require tools Fracking Frequent use of surfactants (wormlike micelles). Can be environmentally harmful Irrigation and drainage systems In emergency situations it allows higher flow rates. Polymers are biodegradable Fire fighting Longer range of jets, but not very successful due to polymer degradation Navigation Possible, but not economic (additive goes away). Polymer-producing sea bacteria? Flowing Matter

4 POLYMER DRAG REDUCTION: DETAILED MEAN FLOW DATA Turbulent pipe flow Mean flow quantities Increased DR: lower f & increased positive shift of log law Escudier et al. JNNFM 81 (1999) 197 Flowing Matter

5 POLYMER DRAG REDUCTION: DETAILED MEAN AND TURBULENT FLOW DATA Turbulent pipe flow Mean flow and turbulent flow quantities (LDA) Three layer model Increased DR: increased positive shift of log law & higher streamwise normal Reynolds stress Pinho & Whitelaw, JNNFM 34 (1990) 129 Flowing Matter

6 POLYMER DRAG REDUCTION Turbulent pipe flow Turbulent flow quantities (LDA) Increased DR: lower azimuthal and radial normal Reynolds stresses (highly anisotropic turbulence) Increased decoupling between u and w,v lower shear Reynolds stress DNS: qualitatively similar behavior Pinho & Whitelaw, JNNFM 34 (1990) 129 Flowing Matter

7 DNS DATA: MEAN FLOW STATISTICS (TCF) DR,Wi DR,Wi DR,Wi DR,Wi Masoudian et al., JoT 17 (2016) in press Flowing Matter Porto, 11-15th January 2016

8 GOVERNING EQUATIONS (INCOMPRESSIBLE): CONTINUITY AND MOMENTUM Continuity: Momentum: u i x i = 0 ρ u i t + ρu k u i = p x i + τ ik Flowing Matter

9 GOVERNING EQUATIONS: VISCOELASTIC CONSTITUTIVE EQUATION Continuity: Momentum: u i x i = 0 ρ u i t + ρu k Constitutive equation: f ( τ kk,p )τ ij,p + λ τ ij,p t f τ kk,p ( ) = exp ελ η p f ( τ ) kk,p = 1+ ελ τ η kk,p p u i = p x i + τ ik τ ij = 2η s D ij!"# + τ ij, p Newtonian solvent + ( u τ ) k ij,p Polymer/ additive τ jk,p u i τ ik,p u j Linearized form of the exponential function D ij = 1 2 ( ) + ξ τ jk,p D ik + τ ik,p D jk Nonlinear terms u i x j + u j x i Flowing Matter αλ τ η ik,p τ kj,p p u = η i p + u j x j x i α=0; ξ=0, ε=0: Upper convected Maxwell model (UCM) or Oldroyd-B (UCM+Newt. solvent) α=0: Phan-Thien Tanner (PTT) model α=0; ξ=0: Simplified PTT model ξ=0, ε=0: Giesekus model (used often for DNS with surfactants) α=0; ε=0: Johnson- Segalman model

10 MULTI BEAD-SPRING MODELS FOR VISCOELASTIC FLUIDS: KINETIC THEORY Bead m Spring connecting beads m and m+1 (m) F spring = 1 (m) F spring Spring connecting beads m-1 and m HR (m) R(m) L max 2 F (m 1) spring + F (m) D + F (m) B = 0 Brownian forces due to collisions on bead m Viscous drag on bead m F (m) D = 3πµ s d!##" u(m) v (m) ξ F (m) B = 2ξkT W! ( t) ( ) C ij = R ir j R 0 2 Second moment of end-to-end vector Difference for beads m and m+1: dr (m) dt = v (m+1) v (m) u (m+1) u (m) R (m). u R (m) R i τ ij,p = nkt N 1 m=1 number density r i (m) r j (m) 1 R (m) 2 2 L max ( N 1)δ ij see Jin & Collins, NJPhysics 9 (2007) 360 Bird et al. Dyn. Pol. Liquids, Vol. 2 (1987) Flowing Matter ensemble averaging r (m) = R (m) a a kt H

11 CONSTITUTIVE EQUATION FOR VISCOELASTIC FLUIDS: CLOSED FORM Finitely extensible nonlinear elastic- Peterlin s closure (FENE-P) τ ij,p = η p λ f (c kk )c ij f (L)δ ij f (c kk ) = L2 3 L 2 c kk f (L) = 1 C ij = R ir j R 0 2 Second moment of end-to-end vector Evolution equation for the conformation tensor c ij c + u ij u t k c i u t jk c j x ik k x k!#### #" ###### $ C ij = 1 λ f (c )c f (L)δ kk ij ij R i Flowing Matter

12 DIMENSIONLESS NUMBERS Fluid properties Ratio of viscosities: β = ν s ν s +ν p (1-β) is proportional to polymer concentration 2 Maximum polymer extensibility (FENE-P): L max Fluid/ flow properties Reynolds number: Re Inertia Viscous = UL ν s +ν p = t diffusion t flow Common definitions in homogeneous in wall turbulence turbulence: Re u τ L ν s +ν p Re = t Taylor ν s K Weissenberg number: Wi Normal stress Shear stress Wi = λu 2 τ ν s +ν p Wi = λ τ η Deborah number: De λ t flow De = λ = λ K t eddy l Valente et al., JFM 760 (2014) 39 Flowing Matter

13 DIRECT NUMERICAL SIMULATIONS: SOME SELF-CONSISTENT VISCOELASTIC Sureshkumar et al., PoF 9 (1997) 743 Channel flow, FENE-P: LDR, low Re t, onset of DR at Wicr, shifted log-law, enhanced u 2, dampened v 2 & w 2, decreased wx, increased streak spacing Dimitropoulos et al., JNNFM 79 (1998) 433 Channel flow, FENE-P (dilute): LDR, low Re t, DR due to Wi and extensional effects Giesekus (more concentrated): DR due also to N2 Partial inhibition of eddies in buffer layer; DR requires enhanced hext Dimitropoulos et al., PoF 13 (2001) 1016 Channel flow, FENE-P: LDR, low Re t, budgets of K, uiuj and wii, inhibition of vortex stretching by high hext Li et al., JNNFM 140 (2006) 23 Channel flow, FENE-P & Oldroyd-B: HDR and MDR (high L 2 and Wi), low and medium Re t (395), vortex structures. Present zero-equation turbulence model Ptasinski et al., FTC 66 (2001) 159 & Ptasinski et al., JFM 490 (2003) 251 Channel flow, PAA, FENE-P: experiments and DNS, production of K by tij,p, LDR to HDR, increase followed by decrease in u 2, reduced pressure strain, budgets of K, energy transferred from mean flow to polymer elastic energy DNS of FENE-P extensively used to develop RANS and LES closures Flowing Matter

14 TURBULENCE RANS MODELS: FENE-P CONSTITUTIVE EQUATION Reynolds decomposition: Mass conservation (incompressible): Momentum equation: ρ U i t â = A + a Instantaneous Fluctuation Reynolds-averaged (upper-case or overbar) Reynolds-averaged equations U k = 0 + ρu k U i = p x i +η s 2 U i ( ρu i u k )+ τ ik,p FENE-P τ ij = 2η s D ij + τ ij,p τ ij,p = η p λ f ( C kk )C ij f ( L)δ ij + η p λ f ( C + c kk kk )c ij RACE c C ij + ij u uk c i u kj + c j ik x k = τ ij,p η p M ij CT ij NLT ij Closures required Flowing Matter

15 DNS FOR CHANNEL FLOW OF FENE-P: DATA ANALYSIS 1 Reynolds-averaged polymer stress τ ij,p = η p λ 0 f ( C kk )C ij f ( L)δ ij + η p λ f ( C kk + c kk )c ij DNS -150 f(c ) C kk 12 f'c' 12 f(c ) C kk 12 f'c' 12 We= 25 DR= 18% We= 100 DR= 37% y + Flowing Matter

16 DNS FOR CHANNEL FLOW OF FENE-P: DATA ANALYSIS 1 Reynolds-averaged polymer stress τ ij,p = η p λ f ( C kk )C ij f ( L)δ ij + η p λ f ( C kk + c kk )c ij 0-50 Reynolds-averaged conformation equation c C ij + ij u uk c i u kj + c j ik x k = f ( C kk )C ij f ( L)δ ij λ M ij CT ij NLT ij -100 DNS: Housiadas et al. PoF 17 (2005) 35106; Li et al., JNNFM 139 (2006) DNS f(c ) C kk 12 f'c' 12 f(c ) C kk 12 f'c' 12 We= 25 DR= 18% We= 100 DR= 37% Oldroyd derivative Mean flow distortion Exact and large Turbulent distortion from distortion in Oldroyd derivative Must be modeled y + from advection, negligible no need for modeling Note: DNS technique used negligible amount of diffusion. Flowing Matter

17 RANS TURBULENCE MODELS FOR FENE-P: CLOSURES FOR Model 1: based on inspection of exact equation for NLT and identification of possible dependencies f ( C mm ) NLT ij λ 2 C E3 u τ = f µ1 C 2 kk u i u j + C α 14 ν 0 ν 0 NLT ij ( u i u k W kn C nj + u j u k W kn C ni + u k u i W jn C ) nk Model 2a&b: based on modelling exact equation for NLT too complex, 5 coefficients + 2 functions f(ckk)*nltxy f(ckk)*nltyy f(ckk)*nltii f(ckk)*nltxy f(ckk)*nltyy f(ckk)*nltii f(ckk)*nltxy f(ckk)*nltyy f(ckk)*nltii DNS First Second Wi=25, DR=18% Flowing Matter y +

18 RANS FOR FENE-P: MODEL FOR THE REYNOLDS STRESS Isotropic models 1) Pinho et al., JNNFM 154 (2008) 89 low Re k-e low DR, NLTij model: simple 2) Resende et al., JNNFM 166 (2011) 639 low & intermediate DR; NLTij model: complex 3) Resende et al., TFC 90 (2013) 69 low Re k-w low & intermediate DR; NLTij model: complex Prandtl-Kolmogorov u i u j = 2ν T S ij 2 3 kδ ij Definitions Model 1: d k ε N =!ε N + 2ν s dy ν T = C µ f µ k 2 2 Modified dissipation!ε N + ε V Viscoelastic stress work ε N = 1 ρ τ ' lk,s ε v = 1 ρ τ ' lk,p u l = ν s u l u l u l = ν p λ ĉlk f ( ĉ mm ) u l ν T = ν N P Model 2a: T ν k 2 k 2 T ν N T = C µ f µ ν P!ε N T = C µ f µ C P µ f P µ C kk!ε N Model 2b: k ν T = C µ f µ ω N Specific rate of dissipation: ω ~ ε k Better behaved than e near walls More sensitive far from walls ω N = ε N k ν N T = f µ ω N ν T P = f µ C µ P f µ P C kk Flowing Matter C µ k k ω N

19 EXACT TRANSPORT EQUATION FOR K: FENE-P Dk Dt = u i u k Exact equation U i k ' u i 1 p'u i 2 k u +ν s ν i s dx i ρ x i x i x i u i + 1 ' τ ik,p u i ρ 1 ρ τ ' ik,p Pk Q N D N e N Q V e V u i DNS Viscoelastic turbulent diffusion Viscoelastic stress work We=25 DR=18% P k Q N Q V D N -ε N -ε V We=100 DR=37% y + P k Q N Q V D N -ε N -ε V When Wi increases Pk decreases e N decreases but high (needs modification of closure) Q V remains small e V increases (requires closure) Flowing Matter

20 CLOSURE FOR VISCOELASTIC TERMS IN K-EQUATION Viscoelastic turbulent diffusion: small but easily modelled Viscoelastic stress work ε V 1 ρ τ ' ik,p u i = ν p λ We=100; DR= 37% C ik f ( C mm + c mm ) u i + c ik f ( C mm + c mm ) u i Pinho et al., JNNFM 154 (2008) 89 Resende et al., JNNFM 166 (2011) 639 ε V = C ε V ( Wi) ν p λ f C mm u ( )c i ik x!"# k NLT ii C ik f' u i / f'c ik u i / SUM Modeled transport equation for k Models 1, 2a & b Nagano & Hishida, JFE 109 (1987) 156 Variable turbulent Prandtl Nagano & Shimada, 9th Turb Shear Flow (1993) Park & Sung, IJHMT 38 (1995) In viscous and buffer sublayer e V is not so important y + Modeled transport equation for e N Models 1 & 2a Nagano & Hishida, JFE 109 (1987) 156 Model 2b Bremberg et al., IJHFF 23 (2002) 731 Model 1: E τ p = 0 Models 2a & b: Closure for E τ p Flowing Matter

21 30 u MODEL ASSESSMENT: FULLY-DEVELOPED CHANNEL FLOW 1: MODELS 2 & 3 Re τ = 395,β = 0.9, L 2 = 900 We= 0 We= 25 }k-ω We= 100 DNS- We= 25 DNS- We= 100 We= 0 } We= 25 k-ε We= 100 u + u + = 11.7 ln y LDR and IDR 7 k DNS- Mansour (We= 0) DNS- We= 25 DNS- We= 100 We= 0 } We= 25 k-ω We= 100 We= 0 We= 25 } k-ε We= 100 k + Problems 10 5 u + = y + u + = 2.5 ln y y k 2 ν T = C µ f µ!ε N + ε V Flowing Matter y +

22 k-e-v 2 -f MODEL FOR FENE-P: THE MAIN IDEA Deficient prediction of k Need to extend to the whole range of Wi, L 2, b Models incorporating wall damping: k-e-v 2 -f Durbin, TCFD 3 (1991) 1 For viscoelastic fluids (FENE-P) Iaccarino et al., JNNFM 165 (2010) 376 Masoudian et al., JNNFM 202 (2013) 99 ρu i u j = 2ρν T S ij 2 3 ρkδ ij kk ν T = C µ!ε C kv 2 µ!ε ν T = C µ v 2 T t Scalar v 2 is like the wall-normal Reynolds stress T t k = max ε,6 N Full Reynolds stress model Leighton et al., APS & ASME (2002,2003) Masoudian et al., IJHFF 54 (2015) 220 ν ε N Extended version of Lai & So s (1990) Minimal changes eij is modelled as by Shima (1988) Lai & So, JFM 221 (1990) 641 Shima, JFE 110 (1988) 38 Very close to the wall Flowing Matter

23 k-e-v 2 -f MODEL (FENE-P): PERFORMANCE Flowing Matter

24 LARGE EDDY SIMULATION (LES): THE IDEA RANS: inherent limitations unsteady flows LES flows with curvature flows with rotation RANS Figures from Sagaut, LES (2000) LES modelling only effects of high wave number Flowing Matter

25 LARGE EDDY SIMULATION (LES): SPATIAL FILTERING OPERATION ϕ = ϕ < +ϕ > Filtered/resolved grid scale (GS) Residual subgrid scale (SGS) model ϕ < (x) = Filtering ϕ(x') Ω G Δ (x x')dx filter Subgrid quantity ϕ > = ϕ ϕ < Note (in general) ( ϕ > ) < 0 in contrast to Reynolds-averaging TEMPORAL LARGE EDDY SIMULATION (TLES): TIME FILTERING OPERATION ϕ = ϕ +ϕ ' Filtering in time t ϕ(t,x) = ϕ ( τ,x)g ( τ t)dτ Temporal gridfiltered quantity Temporal residual quantity Temporal subgrid quantity ϕ ' = ϕ ϕ Flowing Matter

26 EXISTING LES MODELS FOR NON-NEWTONIAN FLUIDS Ohta & Miyashita JNNFM 206 (2014) 29 Inelastic fluid: GNF with power law viscosity equation Turbulent channel flow Modified Smagorinsky model Thais et al., PoF 22 (2010) Viscoelastic: FENE-P Turbulent channel flow: Re t =180; Wimax=138 (L 2 =900,DR=39%), Wimax=115 (L 2 =10000,DR=59%) TLES (form of time domain approximate deconvolution method, TADM) Wang et al., China Phys B 23 (2014) Viscoelastic: FENE-P Uses model of Thais et al. Forced homogeneous isotropic turbulence Accurate SGS models for LES require accurate model of kinetic energy transfer between GS and SGS (not been done previously) Need to investigate forward and backward scatter especially in wall turbulence but also in HIT (DHIT & FHIT)- This has not been done in previous works Flowing Matter

27 TLES: THAIS ET AL, POF 22 (2010) u i t + u i u j x j = p x i + Used very coarse grid Not tried at higher Re: β Re τ 0 2 u i x j 2 M ij x j Resolved sub-filter stress M ij = v i v j v i v j v i = g u i + ( 1 β ) τ v,ij x j + ( 1 β ) S ij x j + χ u Sub-filter term related to nonlinear polymer restoring force Additional diff. equations to compute these extra terms: complex ( ) ( w i u ) i Dissipative regularization term, represents unresolved sub-filter stress w i = f ( u i ) Temporally filtered conformation tensor: extra regularisation and diffusive terms Under-predicts DR: -need to account for secondary regularisation of Cij plus extra sub-filter terms -problems with the shear component (Cxy) DR very sensitive to momentum filter width (absolute variation of DR of 15%) (only 5% for effect of conformation filter width) Flowing Matter

28 LES:GOVERNING EQUATIONS (SPATIAL FILTERING) Momentum equation u i < t < u j < + u i = p< + β x j x i Re τ 0 x j < u i < + u j x j x i τ ij + 1 β x j ( ) τ < v,ij x j FENE-P constitutive equation Resolved polymer stress Sub-grid scale stresses (SGS) tensor: τ ij = ( u i u ) < j u < < i u j τ < = ( η λ) f (c ij,v p kk ) < c < ij f (L)δ ij!##### "##### $ + ( η λ ) ( f (c )c ) < f (c p kk ij kk ) < < c ij!#### #" ###### $ Resolved contribution SGS contribution Evolution equation of the conformation tensor c ij < t + u c < < ij k c x ik k u < < j + c jk < u i < + τ < ij,v η p = FT ij + ST ij Advective term FT ij = u c < c < ij k u ij x k k < ST ij = Distortion term < u c j u ik + c i x jk k x c u < < j ik + c k x jk k x k < u i < Flowing Matter

29 ON-GOING RESEARCH: DEVELOPMENT OF NEW SGS CLOSURES (SPATIAL LES) DNS of turbulent channel flow for viscoelastic fluids Investigation of GS/SGS interactions Effects of Re, Wi, L 2 DNS of homogeneous turbulence for viscoelastic fluids Investigation of GS/SGS interactions Forced turbulence: significant changes observed when l > ttaylor Decaying turbulence. Effects of Re, Wi, L 2 Flowing Matter

30 TCF: EFFECT OF FILTER SIZE - STREAMWISE VORTICITY Ω 11 Ω ij = 1 2 U j x i U i x j Flowing Matter

31 TCF: MOMENTUM-SGS STRESS S < 2S ij < S ij < τ ij 1 3 τ kk δ ij = 2ν SGS S ij < τ ij S < S ij < C s Δ g ( ) 2 τ ij S < S ij < FENE P τ ij S < S ij < Newt SGS attenuated with Wi Modified Newtonian SGS closure may be adequate Masoudian et al., JoT 17 (2016) in press Flowing Matter

32 TCF: POLYMER STRESS CONTRIBUITIONS SGS τ < = ( η λ) ( f (c ij,v p kk )c ) < ij f (c kk ) < < c ij!#### #" ###### $ term 1 Resolved/filtered ( ) f (c kk ) < c ij < f (L)δ ij + η p λ!##### "##### $ term 2 Negligible SGS contribution Flowing Matter

33 TCF: EVOLUTION EQUATION FOR THE CONFORMATION TENSOR c ij < t + u c < < ij k Trace c u < < < j < u ik + c i x jk k HDR + τ < ij,v = FT η ij + ST ij p Shear component FTij is negligible STij requires closure for larger filter sizes especially for shear component Flowing Matter

34 TCF:TRANSPORT EQUATION FOR (TWICE) SGS KINETIC ENERGY 1 τ ii t + τ u < ii j = x j x j ( u i u i ) < u < j u i u i u j ( ) < 2 x i ( p < u < i ( pu i ) < ) + β Re τ x j τ ii x j 2β Re τ u i x j u i x j < u < < u i i x j x j +2 τ u < ij i x j < 2τ ij S! ij Term Q ###!# #" $ classical energy cascade + 2(1 β) ( τ u ) < v,ij i x!### "### j $ Term R 2(1 β) τ < < u v,ij i x j!## "## $ S- GS/SGS exchange ( ) < 2(1 β) τ v,ij S ij!##" ## $ + 2(1 β)τ < < S v,ij! #" ## $ ij Term T U- GS/SGS exchange Diffusive-like terms R+S: can be neglected Viscoelastic stress work-like terms T+U: need closure Flowing Matter

35 SGS DISSIPATION ENERGY IN TCF: BACKWARD/FORWARD SCATTER Backward and forward scatter components of classical cascade (Q) calculated with y + =30 ε = 1 ( 2 ε ε sgs sgs ), ε + = 1 ( 2 ε + ε ) sgs sgs backward' forward' Fraction of points with backscatter Assessed also with other filters Nearly independent of filter size Flowing Matter

36 FORCED HOMOGENEOUS TURBULENCE DNS of decaying homogeneous turbulence for viscoelastic fluids Work in progress Forced HIT From Newtonian up to Wi 15 ε [ s ] ε [ T ] Valente et al., JFM 760 (2014) 39 Valente et al., Under review Flowing Matter

37 FHIT: DECREASING DISSIPATION BY POLYMERS AT LARGE WI Extended range Valente et al., JFM 760 (2014) 39 Valente et al., 67th APS-DFD, S.Fr (2014) For Wi> 15 [ ε s ] [ ] ε T FENE-P Different external forcings N=192 3 and < Retaylor < 180 Polymer loose capability to dissipate energy as Wi Flowing Matter

38 FORCED HIT: DEPLETION OF CLASSICAL CASCADE WITH INCREASING WI Classical cascade (Newtonian) Net non-linear transfer of energy decreases with increasing Wi Scale-by-scale power budget [ f ( κ ) = T ( κ ) + T p ] κ Nonlinear energy transfer spectrum ( ) + 2ν s ( ) [ ] κ 2 E κ F( κ ) = Π( κ ) [ + Π p ] ( κ ) + D( κ ) Energy from k =0 up to k ( ) T κ ' Π κ κ 0 ( )dκ ' [ ε = ε s] = D κ = κ max ( ) Flowing Matter

39 FORCED HIT: DISSIPATED ENERGY AND THE POLYMER-INDUCED CASCADE If non-linear transfer of energy decreases with increasing Wi, but dissipation by solvent increases at large Wi, where does the energy come from? Polymer induced cascade Valente et al., JFM 760 (2014) 39 Valente et al., 67th APS-DFD, S.Fr (2014) Dissipated by the solvent Extracted by the polymer Dissipated by the polymer Flowing Matter

40 FORCED HIT (FHIT): NEW CLOSURES FOR LES (WORK IN PROGRESS) 1 Flowing Matter

41 FHIT: NEW CLOSURES FOR LES (WORK IN PROGRESS) 2 Flowing Matter

42 FHIT: NEW CLOSURES FOR LES (WORK IN PROGRESS) 3 Flowing Matter

43 FHIT:NEW CLOSURES FOR LES (WORK IN PROGRESS) 4 Flowing Matter

44 CLOSURE AND NEW RESEARCH TOPICS RANS type: closed topic for wall turbulence Open topics: recirculating flows, wall-free turbulence, rotation Other constitutive equations FENE versus FENE-P Multi bead-chain models LES type: TLES needs to be further developed Open topic for classical LES (spatial filtering) Surfactants: No specific RANS or LES models available Existing DNS: Giesekus constitutive equation (already years old) Open topic for constitutive equations describing dynamics of wormlike micelles ACKNOWLEDGMENTS Schlumberger EU funding: COMPETE & FEDER Portugal: Fundação para a Ciência e a Tecnologia Brazil: CAPES-CRUP exchange programme and Programme Science without Borders Kazakhstan: British-Kazakh Technical University Flowing Matter