It is of great significance to improve the accuracy of turbulence models in shock-wave/ boundary layer interaction flow. The relationship between the pressure gradient, as well as the shear layer, and the development ...It is of great significance to improve the accuracy of turbulence models in shock-wave/ boundary layer interaction flow. The relationship between the pressure gradient, as well as the shear layer, and the development of turbulent kinetic energy in impinging shock-wave/turbulent bound- ary layer interaction flow at Mach 2.25 is analyzed based on the data of direct numerical simulation （DNS）. It is found that the turbulent kinetic energy is amplified by strong shear in the separation zone and the adverse pressure gradient near the separation point. The pressure gradient was non-dimensionalised with local density, velocity, and viscosity. Spalart Allmaras （S A） model is modified by introducing the non-dimensional pressure gradient into the production term of the eddy viscosity transportation equation. Simulation results show that the production and dissipation of eddy viscosity are strongly enhanced by the modification of S-A model. Compared with DNS and experimental data, the wall pressure and the wall skin friction coefficient as well as the velocity profile of the modified S-A model are obviously improved. Thus it can be concluded that the mod- ification of S-A model with the pressure gradient can improve the predictive accuracy for simulat- ing the shock-wave/turbulent boundary laver interaction.展开更多
RAN S(R eyno lds-averaged N av ier-Stokes)加湍流模型是当前计算飞机粘性流场的最常用方法,数值实践说明要计算大分离流动,需要更高级的方法例如LES(Large Eddy S im u lation)或DN S(D irect N S S im u lation)。然而实际雷诺数下,...RAN S(R eyno lds-averaged N av ier-Stokes)加湍流模型是当前计算飞机粘性流场的最常用方法,数值实践说明要计算大分离流动,需要更高级的方法例如LES(Large Eddy S im u lation)或DN S(D irect N S S im u lation)。然而实际雷诺数下,LES和DN S对网格的要求太高,以至目前还难以应用。DES(D etached-Eddy S im u lation)方法结合了RAN S和LES的优点,通过对Spalart-A llm aras湍流模型中长度尺度的修正,在近壁面它体现为RAN S模型的特点,而在远离物面处又保持LES的亚格子模型的特性。论文对比了采用RAN S和DES方法数值模拟翼型失速特性的能力,并与实验结果进行了对比。结果表明,对大分离流动的数值模拟,DES方法体现出更强的能力。展开更多
基金supported by the National Natural Science Foundation of China (No.11302012,51376001,51136003)the National Basic Research Program of China (No.2012CB720205)+3 种基金the National Magnetic Confinement Fusion Research Program of China (No.2012GB102006)the Aeronautical Science Foundation of China (No.2012ZB51014)the ‘‘111’’ Project(No.B08009)the Astronautical Technology Innovation Foundation of China
文摘It is of great significance to improve the accuracy of turbulence models in shock-wave/ boundary layer interaction flow. The relationship between the pressure gradient, as well as the shear layer, and the development of turbulent kinetic energy in impinging shock-wave/turbulent bound- ary layer interaction flow at Mach 2.25 is analyzed based on the data of direct numerical simulation （DNS）. It is found that the turbulent kinetic energy is amplified by strong shear in the separation zone and the adverse pressure gradient near the separation point. The pressure gradient was non-dimensionalised with local density, velocity, and viscosity. Spalart Allmaras （S A） model is modified by introducing the non-dimensional pressure gradient into the production term of the eddy viscosity transportation equation. Simulation results show that the production and dissipation of eddy viscosity are strongly enhanced by the modification of S-A model. Compared with DNS and experimental data, the wall pressure and the wall skin friction coefficient as well as the velocity profile of the modified S-A model are obviously improved. Thus it can be concluded that the mod- ification of S-A model with the pressure gradient can improve the predictive accuracy for simulat- ing the shock-wave/turbulent boundary laver interaction.
文摘RAN S(R eyno lds-averaged N av ier-Stokes)加湍流模型是当前计算飞机粘性流场的最常用方法,数值实践说明要计算大分离流动,需要更高级的方法例如LES(Large Eddy S im u lation)或DN S(D irect N S S im u lation)。然而实际雷诺数下,LES和DN S对网格的要求太高,以至目前还难以应用。DES(D etached-Eddy S im u lation)方法结合了RAN S和LES的优点,通过对Spalart-A llm aras湍流模型中长度尺度的修正,在近壁面它体现为RAN S模型的特点,而在远离物面处又保持LES的亚格子模型的特性。论文对比了采用RAN S和DES方法数值模拟翼型失速特性的能力,并与实验结果进行了对比。结果表明,对大分离流动的数值模拟,DES方法体现出更强的能力。
