基于MCC理论的内孤立波数值模拟  

Numerical simulation for the internal solitary wave based on MCC theory

作　　者：高原雪[1] 尤云祥[1] 王旭[1] 李巍[1] 

机构地区：[1]上海交通大学海洋工程国家重点实验室,上海200240

出　　处：《海洋工程》2012年第4期29-36,共8页The Ocean Engineering

基　　金：国家863计划资助项目(2010AA09z305);高等学校博士点基金资助项目(20110073130003)

摘　　要：基于MCC(Miyata-Choi-Camassa)理论,将内孤立波诱导上下层深度平均水平速度为入口条件,结合理想流体完全非线性欧拉方程,建立了两层流体中内孤立波生成与传播的CFD(Computational Fluid Dynamics)数值水槽方法。在系列数值模拟基础上,获得了内孤立波设计振幅与数值模拟振幅之间的相关关系,实现了在振幅可控条件下的内孤立波数值模拟。结果表明,在极限振幅范围内,数值模拟所得内孤立波波形均与MCC理论解吻合良好,而KdV(Korteweg-de Vries)和mKdV(modi-fied KdV)理论解只适用于小振幅的情况。同时,利用CFD数值模拟结果,对内孤立波诱导流速场特性进行了分析,结果表明内孤立波诱导水平速度在上层及波面下方流体层中垂向衰减很小,但在内界面与波面之间流体层中垂向衰减明显。Based on MCC（Miyata-Choi-Camassa） theory and fully nonlinear Euler equation for an ideal fluid,a CFD（computational fluid dynamics） numerical method is presented to simulate the generation and propagation of the internal solitary wave in a two-layer fluid,where the velocity-inlet boundary is applied by use of the depth-averaged velocities in the upper-and lower-layer fluids induced by the internal solitary wave.Based on a series of numerically simulated results,the relation between the design and numerically simulated amplitudes is obtained,and a numerical approach is proposed for simulating the internal solitary wave under the condition of giving its amplitude based on such a relation.Results show that the numerically simulated profile for the internal solitary wave has a good agreement with the MCC theory solution in the range of limited amplitudes,while both KdV（Korteweg-de Vries） and mKdV（modified KdV） theories are only suitable for the cases of small amplitudes.Moreover,the characteristics of the velocity fields induced by internal solitary waves are analyzed by use of CFD numerical results,which show that the horizontal velocities in both the upper-layer fluid and below the wave profile decay slowly,but such a horizontal velocity varies sharply in the fluid layer between the interface and wave profile due to the internal solitary wave.

关 键 词：内孤立波 数值水槽 速度入口 MCC理论 

分 类 号：P751[交通运输工程—港口、海岸及近海工程]