低傅氏数兴波数值预报的不稳定现象及其解决方案  

Numerical instability on the wave predition at lower Froude numbers and discussion

作　　者：梁川[1] 赵峰[1] LIANG Chuan;ZHAO Feng(China Ship Scientific Research Center,Wuxi 214082,China)

机构地区：[1]中国船舶科学研究中心,江苏无锡214082

出　　处：《船舶力学》2021年第4期399-405,共7页Journal of Ship Mechanics

基　　金：“十三五”水动力学预研项目(41407010401)。

摘　　要：本文针对船舶在低傅氏(Froude)数兴波数值预报中容易出现计算不稳定的普遍现象,从离散差分格式出发,对控制方程离散格式进行数值分析,推导出船舶CFD所特有的(带自由面)不稳定项形式,从理论上来解释这一现象。同时,根据所推导的数值耗散项的表达形式,提出了低Froude数计算稳定性的控制策略,主要为采用时间一阶隐式格式;减小时间步长;适当加密自由面附近的网格;综合应用前三种策略。Focusing on the general phenomenon that the CFD simulation of the ship wave is prone to numerical instability at lower Froude numbers,this paper starts with the difference scheme of the governing equations,derives the unique instability term for ship CFD solvers due to the existing of the free surface,and finally explains this phenomenon theoretically.The control strategies proposed for the low Froude number cases according to the expression form of the numerical dissipative term deduced are:adopting the first order implicit format for the time term;reducing the time step;refining the grids of the free surface properly;and synthetic application of the previous three strategies.

关 键 词：低Froude数 计算稳定性 船舶CFD 差分格式 

分 类 号：O353.2[理学—流体力学]