Numerical Study Of Compressible Turbulence Model Based On Partial Averaging

The study of turbulence has attracted the attention of the world’s scientific powers.At present,the traditional turbulence model method(Reynolds Averaged Navier-Stokes,RANS)based on the Reynolds-averaged(Navier-Stokes,N-S)equation takes into account the operability,economy and effectiveness in engineering practice,and is the main method to solve engineering practice problems.However,most of the calculation methods oversimplify the physical nature of turbulent flow and heat transfer,and lose important first-order turbulent pulsation information,resulting in many model empirical coefficients,poor universality,and unsatisfactory calculation results.Further improvement is required.Therefore,this paper studies this problem,proposes a method of partial averaging of turbulent pulsation,and establishes a new turbulence model based on this method.This paper deals with the turbulent pulsation velocity based on the partial average method,and establishes a new compressible turbulence model(Partial Average Fluctuation Velocity model,PAFV).Using the finite difference method in the general curve coordinate system,a two-dimensional(Computation Fluid Dynamics,CFD)calculation program was written in python language.Through the numerical calculation of two-dimensional wedge-shaped supersonic flow,two-dimensional flat laminar boundary layer flow,two-dimensional flat plate turbulent boundary layer flow and two-dimensional compression corner supersonic flow,the spatial discrete format of the convective and diffusion terms in the calculation program is verified.accuracy.At last,the two-dimensional cascade flow was calculated.In the two-dimensional cascade flow calculation,the calculation results of the PAFV turbulence model are in good agreement with the cascade surface pressure coefficient calculated by the traditional k-ω turbulence model,and are in good agreement with the experimental values.In the comparison of the turbulent viscosity distribution,it is found that the turbulent viscosity influence area of the k-ω model is mainly concentrated in the leading edge and suction surface of the cascade airfoil,and the attenuation is relatively fast in the wake region of the flow.The turbulent viscosity influence area of the PAFV model is mainly concentrated in the suction surface and wake area of the airfoil,and the transport characteristics of the turbulent viscosity of the PAFV turbulence model are more obvious.In addition,since the PAFV turbulence model uses part of the average pulsation velocity as the turbulent velocity scale,in the region near the shock wave,since the pulsation velocity is suppressed,the turbulent viscosity is also suppressed.The turbulent kinetic energy peaks that occur in the shock region grow too fast and lead to the unfavorable situation of an excessively large turbulent viscosity coefficient.The calculation of the two-dimensional cascade flow by the PAFV compressible turbulence model shows that the model has good applicability in the transonic cascade flow.