有限深密度分层流体中运动物体生成内波的一种等效质量源方法

An equivalent mass source method for internal waves generated by a body moving in a stratified fluid of finite depth

采用一种等效移动质量源来模拟有限深密度分层流体中运动物体生成内波的体积效应和旋涡、湍流尾迹激发源,结合内波本征值问题及Fourier变换等方法,建立了计算运动物体生成内波垂向位移场的一种理论模型,提出了确定移动质量源速度、回转直径及长度的具体方法.利用该理论模型,对一类典型密度分层流体中运动球生成内波的波系与波形结构,以及波高特征等进行了数值模拟与分析,结果与Robey实验结果符合良好,表明了所建立理论模型的合理与有效性.

An equivalent mass source is modeled as excited sources of internal waves generated by the displacement of fluid and the wake of vortex shedding or turbulence due to the body moving in a stratified fluid,a mathematical model for the vertical displacement of internal waves generated by such an equivalent mass source is presented by use of both the associated eigenvalue problem and the Fourier transform method,and the method for estimating the speed,length and diameter of the equivalent mass source is proposed. Calculations based on the proposed method are performed for the generation of internal waves by a towed sphere in a stratified fluid, and the numerical results are in good agreement with the available experimental results of Robey in the kinematic wave patterns and the maximum peak-to-peak amplitude of the internal waves. Such a method may have potentially important applications.