The Numerical Simulation Study Of Whip Performance In Water Entry Of Navigation Body

With the depletion of terrestrial resources and the exploration of marine resources,marine engineering has gradually become one of the deVelopment priorities of the new century.In order to ensure the normal exploitation of marine resources,strengthening military forces has also become a top priority.Unlike land projects,the problems in ocean engineering are more complicated.In addition to the corrosiVe and erosion effects of sea breeze and seawater on the surface of structures,marine engineering equipment is also faced with Various impacts of waVes and seawater.One of the representatiVes is the slamming effect of the naVigating body in the process of entering the water.In addition,in the process of water entering,under the seawater and the caVity interact with each other,the naVigation body's moment is prone to a sudden change at a short time,which will cause a large change in the attitude angle and seriously affects the ballistic stability of the na Vigation body,eVen jumps phenomenon.A lot of scholars at home and abroad haVe done extensiVe research on the process of water entering,but there are few studies on the effect of the whip phenomenon.Therefore,this paper takes torpedo as an example,from the perspectiVe of torpedo sports characteristics,force characteristics and flow field changes,and analyzes a Variety of working conditions,such as the effect of different initial water enter speeds and water enter angles on the whip performance of naVigation body.Based on this,two methods for controlling the whip performance are proposed,and the control effects of different methods are studied.For the torpedo entering process under different working conditions,the torpedo has a large impact force under large speed,and the peak time of the forc e peak and the torque appear earlier.HoweVer,under this condition,the angle of the torpedo changes little.On the contrary,under the small speed,although the impact force of the water inlet is small,the torpedo angle changes greatly,and a serious whip phenomenon occurs.For different angle,the force characteristics of the large angle and the small angle torpedo are not much different at the small speed,and the moment curVes are approximately coincident,so the angle curVes are approximately parallel.At the large speed,the peak of the torpedo moment of the large angle is significantly reduced,and the amplitude of the angle is greatly suppressed.From the control method,increasing the initial angular Velocity of the torpedo into the water can inhibit the torpedo effect of the torpedo to a certain extent,but has little effect on the force characteristics of the torpedo into the water.Changing the head shape can greatly change the force characteristics and flow field changes.The flat-headed torpedo can better suppress the effect of the torpedo in the small water inlet speed and the small water inlet angle condition,but it performs poorly under the conditions of large water inlet speed and large water inlet angle.The hemisphere head torpedo is not much different from the prototype torpedo.