Numerical Study Of Supercavity Flow Of Nonaxisymmetry Cavitator

In modern warfare, underwater weapon is a vital role and the attack speed candirectly affect the process. Maximum speed of traditional underwater weapon is about50-55kn, so how to improve speed of underwater vehicles is really an important issuerecently. Conventional methods of drag reducing such as increasing propulsion power ofengine, applying the technique of polymer viscoelastic material can not achieve the goaland break the limitation of velocity. The development of supercavity show us a goodsolution to this problem.Under supercavity condition, most part of underwater vehicle are covered in a cavityfilled with mixture of vapor, air and water, drag reduction can be up to90%. As aconsequence, the speed can be significantly improved. The key technology is forming asuitable supercavity. So research on cavitator is in urgent need and very important.In this paper, research is focused on nonaxisymmetry cavitator such as disk cavitatorwith grooves or convexes, and comparison is made with results of disk cavitator. Thenumerical simulation of computational fluid dynamics is carried out to analyze threedimentional supercaviting flow, characteristic of cavity shape. The primary work ofnumerical simulation is given as below:Firstly, the numerical model with high accuracy is established through simulatingnatural disk cavity and comparing with semi-empirical formula. Then supercaviting flowformed by cavitator with or without attack angles is studied. Relation between shape ofcavitator and cavity shape, characteristic of flow field are discussed through many cases.Drag and lift properties of different cavitators are measured. Several conclusions aboutinfluence of cavitation number on cavity shape, drag and lift properties are made.The process of ventilated cavity of different cavitators is also investigated ignoringnatural cavity by numerical methods. Cavity shape and characteristic of flow field arediscussed on different cavitation number condition neglecting the effect of gravity or considering gravity respectively. The results of ventilated disk cavity show significantconsistence with natural cavity. The flow field, cavity shape and gas loss of ventilatedcavity are analyzed.