Research On The Characteristics Of High-speed Water-entry Load Of The Vehicle With Slender Head

The role of torpedoes in naval warfare is very important,and new types of launch methods such as aircraft torpedoes have been developed.However,the speed of traditional torpedoes is too low,and modern warfare requires higher speeds for this type of vehicles that crosses the air-water interface and enters the water at high speed.High speed means fast penetration,which can effectively complete the strike against the enemy,but high speed also means that it needs to withstand higher loads during the water entry process.The current load-reducing technology may not be able to meet the needs of the high-speed water-entry process of the vehicles.Therefore,it is of great significance to study the method of reducing the load of the high-speed vehicles in the water-entry process.This article considers the method of adding a slender rod to the head of the traditional vehicles to achieve effective load reduction in the water-entry process,and conducts a systematic study on its water-entry impact load characteristics through numerical simulation.First,based on the basic governing equations of fluid dynamics and turbulence model,using the overlapping grid technology,and using the CFD software STARCCM+,a numerical calculation model for the high-speed water-entry of the slender head-shaped vehicles was established.The numerical model has been studied for grid density independence and time step independence.The effectiven ess of the simulation method is verified by comparison with the existing experimental data.A numerical simulation study was carried out on the process of high-speed vertical water-entry of the slender head-shaped vehicles under typical working conditions,and the variation law of impact load and velocity of the vehicles during the high-speed water-entry process and the load reduction mechanism of the slender rod were analyzed.According to the change of geometric parameters such as the length and diameter of the slender rod,the numerical simulation of the load characteristics was carried out,and the speed change,impact load change and load reduction characteristics of the slender rod model under different lengths and diameters during the impact into the water were obtained..Aiming at the typical slender rod model,the water-entry process under different initial parameters such as water inlet velocity,water inlet angle and other initial parameters was carried out,and the impact load change law and wate r inlet jet development law of the slender rod model water-entry process were obtained.Using statistical tools to quantitatively study the relationship between the initial velocity into the water,the first peak load and the maximum peak load,and obtaine d a series of fitting relationships.The relationship between the peak value of the vertical maximum impact force,the angle of water entry and the initial velocity of water entry and the reason were obtained.