基于梯度增量level-set方法的复杂物体入水砰击数值模拟  

Numerical simulation of water impact of complex body by a gradient-augmented level set method

作　　者：石伏龙 李洪鑫 辛建建 袁琪 季孟洁 SHI Fu-ong;LI Hong-xin;XIN Jian-jian;YUAN Qi;JI Meng-jie(School of Shipping and Naval Architecture,Chongqing Jiaotong University,Chongqing 400074,China;Institute of Naval Architecture and Ocean Engineering,Ningbo University,Ningbo 315211,China)

机构地区：[1]重庆交通大学航运与船舶工程学院,重庆400074 [2]宁波大学海运学院,浙江宁波315211

出　　处：《船舶力学》2024年第6期877-886,共10页Journal of Ship Mechanics

基　　金：国家自然科学基金青年项目(51909124);重庆市教委科学技术青年项目(KJQN202100704);2022年重庆市研究生科研创新项目(2022S0047)。

摘　　要：复杂结构物自由表面砰击问题,如空投鱼雷、水空无人航行器潜水和高速船出入水,一直是海洋工程领域的研究热点。本文采用梯度增量level-set和虚拟网格法数值模拟复杂结构物的入水砰击,采用时间半隐式有限差分法求解不可压缩Navier-Stokes方程,虚拟网格法可重构复杂结构物界面插值模块并施加无滑移边界条件,梯度增量level-set法可捕捉非线性自由表面翻卷、射流等物理现象。基于以上方法模拟二维圆柱的常速入水砰击,并与试验和数值结果对比,验证本文数值方法的正确性。最后,数值模拟二维船型剖面和飞机剖面的入水砰击,分析了冲击压力、运动响应、压力分布和自由表面运动随入水角度的变化规律。同时,通过模拟可观察到复杂结构浸入水中后的流体分离、射流和小角度空气腔等典型砰击物理现象。Free surface impact of complex structures,such as airdrop torpedo,the diving of unmanned under-water vehicles,and the water impact of high-speed ships,has always been a research hotspot in the field of ocean engineering.This paper presents the simulation of water impact of complex structures by combining the ghost cell method and the gradient augmented level set method(GALS).A time semi-implicit finite differ-ence method was used to solve the incompressible Navier-Stokes equations,the ghost cell method was used to enforce the no-slip boundary conditions by interface reconstruction,and the gradient augmented level set method was used to capture nonlinear free surfaces such as wave overturning and jet flows.The slamming of a two-dimensional cylinder at constant speed was simulated to validate the accuracy of this numerical meth-od by comparing the present results with the experimental data.Upon simulation of the slamming of a two-di-mensional hull section,the variation rules of the impulsive pressure,the motion response,the pressure distri-bution,and the free surface motion with respect to the relative impact angle were analyzed.Also,some typi-cal impact phenomena were observed such as the flow separation,the jet flow,and the ventilation for a small impact angle.

关 键 词：虚拟网格 浸入边界法 levelset 砰击 复杂结构 

分 类 号：O353.4[理学—流体力学]