摘要
采用高精度差分格式求解非定常可压缩Ｎａｖｉｅｒ－Ｓｔｏｋｅｓ方程，对激波－单涡／双涡相互干扰产生的声场进行了直接数值模拟。详细研究了波－涡干扰声场结构的早期发展阶段，将激波－单涡的计算结果和相应实验进行了对比，并给出近场声压的衰减规律。在此基础上模拟较为复杂的激波－双涡干扰，给出不同旋涡旋转方向下的声场结构。
By using the direct numerical simulation, two-dimensional flows produced by the interactions between a shock and a single vortex or a pair of vortices are studied. The fully compressible Navier-Stokes equations are solved by fifth-order accurate upwind compact scheme for spatial derivatives together with the fourth-order accurate Runge-Kutta scheme for time integration. A series of time-dependent numerical simulation results are presented. The effects of the strengths of shock and vortices on the flow fields are examined. The characteristics of near-field sound generated by the interactions are underscored. The deformation of the shock structure is analyzed. Within the interaction region, pressure gradient in the direction parallel to the shock is created and then promotes the generation of secondary reflected shock. The generation of acoustic is associated with the deformation of the shock structure. For the case of a single vortex, two kinds of acoustic waves are observed: precursor and second sound. Both of them are of quadrupolar nature. The circumferential distribution of sound pressure is compared to other results. It is shown that present result from Navier-Stokes equation is in good agreement with corresponding experimental result and Euler solution. It is also found that the decay of the sound pressure is inversely proportional to r^{4/5} in the near-field. For the case of pair of vortices, the flow field and sound generated by the interactions differs significantly depending on the rotational direction of vortices.
出处
《力学学报》
EI
CSCD
北大核心
2001年第6期721-728,共8页
Chinese Journal of Theoretical and Applied Mechanics
关键词
气动声学
涡波干扰
紧致差分格式
数值模拟
可压缩流
声场
aeroacoustics, shock-vortex interaction, numerical simulation, compact difference scheme, compressible flow
