摘要
目的 研究空间局部高剪切区中小尺度扰动随机化的物理机制 .方法 对小尺度运动四波相互作用模型进行数值分析 .结果 在速度剪切度增大到一定程度时 ,将会出现小尺度扰动的混沌行为 ,它导致局部高剪切区中湍斑的产生 .结论 小尺度扰动的混沌行为具有与大尺度运动不同的新机制 .在包含角动量平衡方程的新的流体力学方程组的基础上 。
Aim To investigate the physical mechanisms of randomization of the small scale disturbances in local high shear regions in shear flows. Methods The four wave interaction model equations for small scale disturbances were analyzed numerically. Results As the velocity shear increases to a certain extent, the small scale disturbances will exhibit chaotic behavior, which leads to the production of turbulent spots in local high shear regions. Conclusion The chaotic behavior of the small scale motion originates from a different mechanism from that for the large scale motion. On the basis of the new hydrodynamic equations that include a conservation equation of angular momentum, the laminar turbulent transition of shear flows through secondary instability and the direct transition from laminar to turbulent flow taking place under some conditions can be explained consistently.
出处
《北京理工大学学报》
EI
CAS
CSCD
1999年第6期673-677,共5页
Transactions of Beijing Institute of Technology
