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Journal of Hydrodynamics 2022年第3期34卷 408-421页

作者： Ming-Kang Li Shuai Zhang Yu-Xiang Peng A-Man Zhang College of Shipbuilding Engineering Harbin Engineering UniversityHarbin150001China Nanhai Institute of Harbin Engineering University Sanya572024China School of Marine Engineering and Technology Sun Yat-sen UniversityZhuhai519082China

The collapse of a cavitation bubble is an interesting topic and it has many applications in the engineering fields.Due to its compressible nature,the modelling of a cavitation bubble is not easy by the Lagrangian method,like the smoothed particle hydrodynamics(SPH),as there is large variation of particle volume.Currently,there are two kinds of method that have been proposed to deal with this problem:the particle regeneration technique(PRT)and the volume adaptive scheme(VAS).They have all been validated via several numerical tests of compressible flow in the past studies.As is based on totally different concept,the ultimate simulation results and properties may differ.Here,we intend to compare these two methods based on the Riemann-based SPH solver with monotone upwind-centered scheme for conservation laws(MUSCL)reconstruction via several numerical tests.The characteristics of these two methods are discussed and the applicable scope for them are also commented for further usage.

关键词： compressible flow smoothed particle hydrodynamics(SPH) particle regeneration technique(PRT) volume adaptive scheme(VAS)

A parallel methodology of adaptive Cartesian grid for compressible flow simulations

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Advances in Aerodynamics 2022年第1期4卷 449-478页

作者： Xinyu Qi Yuchen Yang Linlin Tian Zhenming Wang Ning Zhao College of Aerospace Engineering Nanjing University of Aeronautics and AstronauticsNanjing210016China State Key Laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and AstronauticsNanjing210016China

The combination of Cartesian grid and the adaptive mesh refinement(AMR)technology is an effective way to handle complex geometry and solve complex flow problems.Some high-efficiency Cartesian-based AMR libraries have been developed to handle dynamic changes of the grid in parallel but still can not meet the unique requirements of simulating flow around objects.In this paper,we propose an efficient Cartesian grid generation method and an information transmission approach for the wall boundary to parallelize the implementation of ghost-cell method(GCM).Also,the multi-valued ghost-cell method to handle multi-value points is improved to adapt to the parallel framework.Combining the mentioned methodologies with the open-source library p4est,an automatic and efficient simulation of compressible flow is achieved.The overall performance of the methodology is tested through a wide range of inviscid/viscous flow cases.The results indicate that the capability and parallel scalability of the present numerical methodology for solving multiple types of flows,involving shock and vortices,multi-body flow and unsteady flows are agreeable as compared with related reference data.

关键词： Cartesian grids AMR Parallel computing compressible flow Immersed boundary method

A new dynamic subgrid-scale model using artificial neural network for compressible flow

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Theoretical & Applied Mechanics Letters 2022年第4期12卷 267-274页

作者： Han Qi Xinliang Li Ning Luo Changping Yu LHD Institute of MechanicsChinese Academy of SciencesBeijing 100190China School of Engineering Science University of Chinese Academy of SciencesBeijing 100049China State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and TechnologyXuzhou 221116China

The subgrid-scale(SGS)kinetic energy has been used to predict the SGS stress in compressible flow and it was resolved through the SGS kinetic energy transport equation in past studies.In this paper,a new SGS eddy-viscosity model is proposed using artificial neural network to obtain the SGS kinetic energy precisely,instead of using the SGS kinetic energy equation.Using the infinite series expansion and reserving the first term of the expanded term,we obtain an approximated SGS kinetic energy,which has a high correlation with the real SGS kinetic energy.Then,the coefficient of the modelled SGS kinetic energy is resolved by the artificial neural network and the modelled SGS kinetic energy is more accurate through this method compared to the SGS kinetic energy obtained from the SGS kinetic energy equation.The coefficients of the SGS stress and SGS heat flux terms are determined by the dynamic procedure.The new model is tested in the compressible turbulent channel flow.From the a posterior tests,we know that the new model can precisely predict the mean velocity,the Reynolds stress,the mean temperature and turbulence intensities,etc.

关键词： Subgrid-scale kinetic energy Eddy-viscosity model compressible flow

compressible flow characteristics around a biconvex arc airfoil in a channel

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Propulsion and Power Research 2014年第1期3卷 29-40页

作者： Md.Abdul Hamid A.B.M.Toufique Hasan S.M.Alimuzzaman S.Matsuo T.Setoguchi Department of Mechanical Engineering Bangladesh University of Engineering and Technology(BUET)Dhaka-1000Bangladesh Department of Advanced Technology Fusion Saga UniversitySaga 8408502Japan

Shock wave-boundary layer interactions(SWBLI)are observed in several practical high-speed internal flows,such as compressor blades,turbine cascades,nozzles and so on.Shock induced oscillations(SIO),aerodynamic instabilities so-called buffet flows,flutter,aeroacoustic noise and vibration are the detrimental consequences of this unsteady shockboundary layer interactions.In the present study,a numerical computation has been performed to investigate the compressible flow characteristics around a 12%thick biconvex circular arc airfoil in a two dimensional channel.Reynolds averaged Navier-Stokes equations with two equation k-ωshear stress transport(SST)turbulence model have been applied for the computational analysis.The flow field characteristics has been studied from pressure ratio(ratio of back pressure,pb to inlet total pressure,p01)of 0.75 to 0.65.The present computational results have been compared and validated with the available experimental data.The results showed that the internal flow field characteristics such as shock wave structure,its behavior(steady or unsteady)and the corresponding boundary layer interaction are varied with pressure ratio.Self-excited shock oscillation was observed at certain flow conditions.Moreover,the mode of unsteady shock oscillation and its frequency are varied significantly with change of pressure ratio.

关键词： compressible flow Shock waves Shock induced oscillation Frequency Reynolds-averaged Navier-Stokes(RANS)

A discrete Boltzmann model with symmetric velocity discretization for compressible flow

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Chinese Physics B 2023年第11期32卷 374-382页

作者：林传栋孙笑朋苏咸利赖惠林方晓 Sino-French Institute of Nuclear Engineering and Technology Sun Yat-sen UniversityZhuhai 519082China School of Mathematics and Statistics the Key Laboratory of Analytical Mathematics and Applications(Ministry of Education)Fujian Key Laboratory of Analytical Mathematics and Applications(FJKLAMA)and Center for Applied Mathematics of Fujian Province(FJNU)Fujian Normal UniversityFuzhou 350117China

A discrete Boltzmann model(DBM) with symmetric velocity discretization is constructed for compressible systems with an adjustable specific heat ratio in the external force field. The proposed two-dimensional(2D) nine-velocity scheme has better spatial symmetry and numerical accuracy than the discretized velocity model in literature [Acta Aerodyn. Sin.40 98108(2022)] and owns higher computational efficiency than the one in literature [Phys. Rev. E 99 012142(2019)].In addition, the matrix inversion method is adopted to calculate the discrete equilibrium distribution function and force term, both of which satisfy nine independent kinetic moment relations. Moreover, the DBM could be used to study a few thermodynamic nonequilibrium effects beyond the Euler equations that are recovered from the kinetic model in the hydrodynamic limit via the Chapman–Enskog expansion. Finally, the present method is verified through typical numerical simulations, including the free-falling process, Sod’s shock tube, sound wave, compressible Rayleigh–Taylor instability,and translational motion of a 2D fluid system.

关键词： discrete Boltzmann method compressible flow nonequilibrium effect kinetic method

Achieving acoustic cloak by using compressible background flow

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Chinese Physics B 2016年第8期25卷 242-250页

作者：张若洋赵清葛墨林 Theoretical Physics Division Chern Institute of Mathematics Nankai University School of Physics Beijing Institute of Technology

We propose a scheme of acoustic spherical cloaking by means of background irrotational flow in compressible fluid.The background flow forms a virtual curved spacetime and directs the sound waves to bypass the cloaked objects. To satisfy the laws of real fluid, we show that spatially distributed mass source and momentum source are necessary to supply. The propagation of sound waves in this system is studied via both geometric acoustics approximation and full wave approach.The analytic solution of sound fields is obtained for plane wave incidence. The results reveal the effect of phase retardation（or lead） in comparison with the ordinary transformation-acoustic cloak. In addition, the ability of cloaking is also evaluated for unideal background flows by analyzing the scattering cross section.

关键词： invisibility cloaking transformation acoustics compressible flow

A Nonlinear Sub-grid Scale Model for compressible Turbulent flow

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Chinese Journal of Aeronautics 2007年第6期20卷 495-500页

作者： Li Bin Wu Songping School of Aeronautic Science and Engineering Beijing University of Aeronautics and Astronautics Beijing 100083 China

The governing equations for large eddy simulation （LES） are obtained by filtering the Navier-Stokes （N-S） equations with standard （non-Favre filtering） spatial filter function. The filtered scale stress due to the standard filtering is then reconstructed by using the Taylor series expansion. The loss of information due to truncating the expansion up to the first derivative term is modeled by a dynamic nonlinear model （DNM）, which is free from any empirical constant and wall damping function. The DNM avoids the singularity of the model and shows good local stability. Unlike the conventional dynamic Smagorinsky model （DSM）, the DNM does not require the plane averaging and reduces the computational cost. The turbulent flow over a double ellipsoid for Reynolds number of 4.25 × 10^6 and Mach number of 8.02 is simulated numerically to validate the proposed approach. The results are compared with experiment data, as well as the data of Reynolds averaged numerical simulation （RANS）.

关键词： large eddy simulation subgrid scale compressible flow nonlinear

Constrained Large-Eddy Simulation of compressible flow Past a Circular Cylinder

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Communications in Computational Physics 2014年第2期15卷 388-421页

作者： Renkai Hong Zhenhua Xia Yipeng Shi Zuoli Xiao Shiyi Chen State Key Laboratory for Turbulence and Complex Systems College of EngineeringPeking UniversityBeijing 100871P.R.China. Center for Applied Physics and Technology College of EngineeringPeking UniversityBeijing 100871P.R.China

compressible flow past a circular cylinder at an inflow Reynolds number of 2×105 is numerically investigated by using a constrained large-eddy simulation(CLES)technique.Numerical simulation with adiabatic wall boundary condition and at a free-stream Mach number of 0.75 is conducted to validate and verify the performance of the present CLES method in predicting separated flows.Some typical and characteristic physical quantities,such as the drag coefficient,the root-mean-square lift fluctuations,the Strouhal number,the pressure and skin friction distributions around the cylinder,etc.are calculated and compared with previously reported experimental data,finer-grid large-eddy simulation(LES)data and those obtained in the present LES and detached-eddy simulation(DES)on coarse grids.It turns out that CLES is superior to DES in predicting such separated flow and that CLES can mimic the intricate shock wave dynamics quite well.Then,the effects of Mach number on the flow patterns and parameters such as the pressure,skin friction and drag coefficients,and the cylinder surface temperature are studied,with Mach number varying from 0.1 to 0.95.Nonmonotonic behaviors of the pressure and skin friction distributions are observed with increasing Mach number and the minimum mean separation angle occurs at a subcritical Mach number of between 0.3 and 0.5.Additionally,the wall temperature effects on the thermodynamic and aerodynamic quantities are explored in a series of simulations using isothermal wall boundary conditions at three different wall temperatures.It is found that the flow separates earlier from the cylinder surface with a longer recirculation length in the wake and a higher pressure coefficient at the rear stagnation point for higher wall temperature.Moreover,the influences of different thermal wall boundary conditions on the flow field are gradually magnified from the front stagnation point to the rear stagnation point.It is inferred that the CLES approach in its current version is a useful and effective tool for simu

关键词： compressible flow constrained large-eddy simulation circular cylinder separated flow.

Upwind and High-Resolution Methods for compressible flow:From Donor Cell to Residual-Distribution Schemes

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Communications in Computational Physics 2006年第2期1卷 192-206页

作者： Bram van Leer W.M.Keck Foundation Laboratory for Computational Fluid Dynamics Department of Aerospace EngineeringThe University of MichiganAnn ArborMI 48108-2140USA

In this paper I review three key topics in CFD that have kept researchers busy for half a century.First,the concept of upwind differencing,evident for 1-D linear advection.Second,its implementation for nonlinear systems in the form of highresolution schemes,now regarded as classical.Third,its genuinely multidimensional implementation in the form of residual-distribution schemes,the most recent addition.This lecture focuses on historical developments;it is not intended as a technical review of methods,hence the lack of formulas and absence of figures.

关键词： Upwind difference high-resolution method compressible flow nonlinear conservation laws

COMPUTATION　OF　compressible　flow　PAST　SLENDER　WING－BODY　USING　FULL－POTENTIAL　EQUATION

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Chinese Journal of Aeronautics 1996年第1期9卷 1-5页

作者： Huang Mingke(Department of Aerodynamics, Nanjing University of Aeronautics and Astronautics, Nanjing, China, 210016) Department of Aerodynamics Nanjing Univ. Aero. and Astronaut. Nanjing 210016 China

The H-O grid is suggested to compute compressible flow past highly swept slender wing-body combinations. Full-potential equation, finite difference method and approximate factorization scheme are used. The computations for the AGARD-B wing-body show that the code developed can apply to the cases from subsonic up to low supersonic free stream. The computed lift and pitching moment are in good agreement with the experimental results.

关键词： grids compressible flow sweepback finite difference theory subsonic flow supersonic flow