基频涡卷群并作用的唯象模型与数值分析

Phenomenological model and numerical analysis of collective interaction of primary vortex

摘要

摘要:基于线性稳定性理论, 建立了可压缩时间发展混合层亚谐扰动作用的唯象分析图, 用以分析并判定亚谐扰动相差对基频涡卷非线性演化类型的影响, 据此导出了基频涡卷各非线性演化类型的定量的相差唯象模型. 研究发现, 对于单一亚谐扰动作用, 基频涡卷的演化类型可归纳为撕裂、中心对称群并和非对称群并3类演化现象. 撕裂现象和中心对称群并是特殊现象, 对应特定的相差点; 非对称群并为常见现象, 对应除这些相差点之外的相差区间, 并以逐级对并方式进行.

Abstract:A phenomenological model of collective interaction of primary vortex of mixing layers is built on the linear stability theory in this paper. The model can be used to determine the influence of the phase shift of the subharmonic disturbance wave on the nonlinear evolving process of the primary vortex. The results indicate that the evolving process of the primary vortex can be classified as tearing phenomenon, symmetric collective interaction and asymmetrical collective interaction. The tearing phenomenon and symmetric collective interaction are special phenomena and occur only at particular phase shift points, while the asymmetrical collective interaction is common and proceed through pairing one by one.