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Extension of Near-Wall Domain Decomposition to Modeling Flows with laminar-turbulent transition

Communications in Computational Physics 2022年第2期31卷 645-668页

作者： M.Petrov S.Utyuzhnikov A.Chikitkin N.Smirnova Moscow Institute of Physics&Technology Dolgoprudny 141700Russia Department of Mechanical Aerospace&Civil EngineeringThe University of ManchesterManchesterM139PLUK

The near-wall domain decomposition method(NDD)has proved to be very efficient for modeling near-wall fully turbulent flows.In this paper the NDD is extended to non-equilibrium regimeswith laminar-turbulent transition(LTT)for the first time.The LTT is identified with the use of the e^(N)-method which is applied to both incompressible and compressible flows.TheNDD ismodified to take into account LTT in an efficientway.In addition,implementation of the intermittency expands the capabilities of NDD to model non-equilibrium turbulent flows with transition.Performance of the modified NDD approach is demonstrated on various test problems of subsonic and supersonic flows past a flat plate,a supersonic flow over a compression corner and a planar shock wave impinging on a turbulent boundary layer.The results of modeling with and without decomposition are compared in terms of wall friction and show good agreement with each other while NDD significantly reducing computational resources needed.It turns out that the NDD can reduce the computational time as much as three times while retaining practically the same accuracy of prediction.

关键词： Domain decomposition laminar-turbulent transition interface boundary condition near-wall flow low-Reynolds-number model

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A dual-eddy EMMS-based turbulence model for laminar-turbulent transition prediction

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Particuology 2021年第5期19卷 285-298页

作者： Shuyu Guo Limin Wang State Key Laboratory of Multiphase Complex Systems Institute of Process EngineeringChinese Academy of SciencesBeijing 100190China School of Chemical Engineering University of Chinese Academy of SciencesBeijing 100049China Innovation Academy for Green Manufacture Chinese Academy of SciencesBeijing 100190China

Turbulence is a century-old physics problem,and the prediction of laminar-turbulent transition remains a major challenge in computational fluid dynamics(CFD).This paper proposes a new conceptual multiscale-structure flow system consisting of a nonturbulent part and two types of turbulent eddies with different properties.The stability criterion for turbulent transition flows,based on the principle of compromise-in-competition between viscosity and inertia,is used to obtain model closure.The multiscale-structure concept and stability criterion are the characteristics of the dual-eddy energy-minimization multiscale(EMMS)-based turbulence model.The solved heterogeneous structure parameters and energy dissipation rate are analyzed,which reveal the laminar-turbulent transition process.To validate the dual-eddy EMMS-based turbulence model,three benchmark problems,namely,the transitional flows over the flat plate boundary layer with zero pressure gradient,NACA0012,and Aerospatiale-A airfoils,were simulated.The simulation was performed by combining the optimized results from the proposed model with the equations of the well-known κ-ω shear stress transfer(SST)turbulence model.The numerical results show that the dual-eddy EMMS-based turbulence model improves the prediction in the laminar-turbulent transition process.This demonstrates the soundness of using the multiscale-structure concept in turbulent flows to establish the turbulence transition model by considering the principle of compromise-in-competition between viscosity and inertia.

关键词： turbulent flows laminar-turbulent transition EMMS Turbulence model Multiscale structure

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Adjoint-based robust optimization design of laminar flow wing under flight condition uncertainties

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Chinese Journal of Aeronautics 2023年第6期36卷 19-34页

作者： Yifu CHEN Hanyue RAO Yiju DENG Tihao YANG Yayun SHI Junqiang BAI School of Aeronautics Northwestern Polytechnical UniversityXi’an 710072China The First Aircraft Design and Research Institute Xi’an 710089China State Key Laboratory for Strength and Vibration of Mechanical Structures School of Aerospace EngineeringXi’an Jiaotong UniversityXi’an 710049China

It is an inherent uncertainty problem that the application of laminar flow technology to the wing of large passenger aircraft is affected by flight conditions.In order to seek a more robust natural laminar flow control effect,it is necessary to develop an effective optimization design method.Meanwhile,attention must be given to the impact of crossflow(CF)instability brought on by the sweep angle.This paper constructs a robust optimization design framework based on discrete adjoint methods and non-intrusive polynomial chaos.transition prediction is implemented by coupled Reynolds-Averaged Navier-Stokes(RANS)and simplified e^(N)method,which can consider both Tollmien-Schlichting(TS)wave and crossflow vortex instability.We have performed gradient enhancement processing on the general Polynomial Chaos Expansion(PCE),which is advantageous to reduce the computational cost of single uncertainty propagation.This processing takes advantage of the gradient information obtained by solving the coupled adjoint equations considering transition.The statistical moment gradient solution used for the robust optimization design also uses the derivatives of coupled adjoint equations.The framework is applied to the robust design of a 25°swept wing with infinite span in transonic flow.The uncertainty quantification and sensitivity analysis on the baseline wing shows that the uncertainty quantification method in this paper has high accuracy,and qualitatively reveals the factors that dominate in different flow field regions.By the robust optimization design,the mean and standard deviation of the drag coefficient can be reduced by 29%and 45%,respectively,and compared with the deterministic optimization design results,there is less possibility of forming shock waves under flight condition uncertainties.Robust optimization results illustrate the trade-off between the transition delay and the wave drag reduction.

关键词： Adjoint method Gradient-based optimization laminar-turbulent transition Robust design Uncertainty propagation

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On properties of the deterministic turbulence and reproducibility of its instantaneous and statistical characteristics

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Theoretical & Applied Mechanics Letters 2014年第6期4卷 1-19页

作者： Vladimir I.Borodulin Yury S.Kachanov Khristianovich Institute of Theoretical and Applied Mechanics of the Russian Academy of Sciences

As known from previous studies, is a post-transitional flow that is turbulent the deterministic turbulence （DeTu） according to the generally accepted statistical characteristics but possesses, meanwhile, a significant degree of determinism, i.e., reproducibility of its instantaneous structure. It is found that the DeTu can occur in those cases when transition is caused by convective instabilities; in boundary layers, in particular. The present paper is devoted to a brief description of history of discovering the DeTu phenomenon, as well as to some recent advance in investigation of instantaneous and statistical properties of such turbulent boundary layer flows.

关键词： boundary layer laminar-turbulent transition deterministic wall turbulence instantaneous characteristics statistical characteristics reproducibility

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laminar-turbulent Bifurcation Scenario in 3D Rayleigh-Benard Convection Problem

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Open Journal of Fluid Dynamics 2016年第4期6卷 496-539页

作者： Nikolay M. Evstigneev Laboratory of Chaotic Dynamical Systems Institute for System Analysis Russian Academy of Science Moscow Russia

We are considering two initial-boundary value problems for Rayleigh-Benard convection in Oberbeck-Boussinesq approximation for incompressible fluid in 3D-rectangular domain with 4:4:1 geometric ratio with periodicity in two directions and cubic domain with 1:1:1 ratio and zero velocity and temperature gradient boundary conditions. For this purpose, we use two numerical method: one is a Pseudo-Spectral-Galerkin method with trigonometric-Chebyshev polynomials and the other is finite element/volume method with WENO interpolation for advection term. Numerical methods are presented shortly and are benchmarked against known DNS data and against one another (for quasi-periodic domain problem). Then we perform stability analysis using analytical expression for main stationary solutions and eigenvalue numerical analysis by applying Implicitly Restarted Arnoldi (IRA) method. The IRA is used to perform linear stability analysis, find bifurcations of stationary points and analyze eigenvalues of monodromy matrices. Thus characteristic exponents of the system for time periodic solutions (limited cycles of various periods and resonance invariant tori) are computed. We show, numerically, the existence of multistable rotes to chaos through chaotic fractal attractors, full Feigenbaum-Sharkovski cascades and multidimensional torus attractors (Landau-Hopf scenario). The existence of these attractors is shown through analysis of phase subspaces projections, Poincare sections and eigenvalue analysis of numerically computed DNS data. These attractors burst into chaos with the increase of Rayleigh number either through resonance and phase-locking or through emergence of singular chaotic attractors.

关键词： Rayleigh-Benard Convection Direct Numerical Simulation laminar-turbulent transition Bifurcations Nonlinear Dynamics Turbulence Chaos

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TURBULENCE IN STENOSES: SURVEY AND EARLY NUMERICAL RESULTS

TURBULENCE IN STENOSES: SURVEY AND EARLY NUMERICAL RESULTS

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第4届国际流体力学学术会议

作者： N.B.Wood X.Y.Xu Faculty of Engineering Imperial College London London SW7 2AZ UK Faculty of Engineering Imperial College London London SW7 2AZ UK

＜正＞Haemodynamic numerical computations in arteries may be applied to flow through stenoses and the resultant forces affecting plaque rupture. Occlusions may promote disturbed flow, sometimes leading to laminar turbulent transition, with potential implications for rupture. Most numerical studies have been limited to ’laminar’ flow, but turbulence requires special methods. The data on turbulent transition in occlusions are varied, with little systematic analysis, because of the difficulty in distinguishing disturbed flow from turbulent flow, and the influence of the wide range of occlusion geometry on flow development. Initial results from a modern turbulence model applied to a smooth symmetrical stenosis are presented.

关键词： stenoses laminar-turbulent transition turbulence simulation turbulence modelling.

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