可压缩双组分混合层的直接数值模拟研究

通过数值求解可压缩Navier-Stokes方程模拟了三维可压缩双组分混合层问题,着重研究了双组分密度比和可压缩效应对混合层发展演化的影响.研究表明,随着密度比的增大,混合层扰动增长率降低.在混合层发展初期,可压缩性作用尤其是斜压效应对旋涡的发展起主导作用;在混合层发展后期,可压缩性影响减弱,旋涡的拉伸扭转效应占主导作用.同时,还分析讨论了可压缩混合层中湍流的转捩及拟序结构的演化过程.

Direct numerical simulation of compressible binary species mixing layer

Compressible binary species mixing layer was investigated using direct numerical simulation to solve the three-dimensional compressible Navier-Stokes and species equations.The effects of the density ratio of binary species and compressible effect were mainly discussed.Results show that,as the density ratio increases,the growth rate of the disturbances in the mixing layer decreases.In the early stage of the the mixing layer evolution,the compressible effect,especially the baroclinic effect,dominates the dynamics of the vortex;in the later stage,the compressibility becomes weak and the stretching effect plays a dominant role.The transition and evolution of the coherent structures were also analyzed.