弱剪切平面湍流射流的直接数值模拟

Direct Numerical Simulation of a Weak-Shearing Plane Turbulent Jet

采用直接数值模拟方法研究了弱剪切平面湍流射流的涡量场。其中"弱剪切"是指射流出口速度与伴随流速度的大小在同一数量级(文中为2∶1)。计算结果精确捕捉到了大涡卷起、两涡配对及特殊的三涡合并现象。纵向速度U的平均分布与实验值符合得很好。由于涡量场关于射流轴线的完全对称性,雷诺应力的分布较为特殊。

Direct numerical simulation has been used to study the vorticity field of a weakshearing plane turbulent jet, where 'weakshearing' refers to the magnitudes of the jet exit velocity and the coflow velocity being same (2∶1 in this paper). The simulation results capture precisely the phenomena of the rollingup of spanwise vortexes, the paring of two vortexes and the mixing progress of three vortexes. The mean profile of the longitudinal velocity U compares well with the experimental results. The profiles of Reynods stresses look special due to the complete symmetry about the jet centerline of the vorticity field. Figs 6 and refs 8.