Research On Kinematic Characteristics Of Moving Object During Water-skipping

The common phenomenon of stone skipping in life and the jumping return mode adopted by spacecraft are all typical bouncing motion processes.When the moving object skips on the water surface,the movement process includes the multiphase coupling action of solid,liquid and gas,which involves many subjects such as hydrodynamics,rigid body dynamics and so on.In this paper,theoretical and experimental research methods are used to analyze and study the kinematic characteristics of the moving object in the process of water-skipping.The main research contents and achievements are as follows:In order to solve the problem of force in bouncing of moving object,two kinds of mechanical models are established based on Von Karman impact model and thin airfoil theory.Then,the numerical calculation of the two models are carried out and the influence of the motion parameters on mechanical properties is obtained.The3-DOF dynamic equation of plate-skipping is derived,and the two mechanical models are verified respectively,and the calculation method is determined.The numerical calculation of the small angle water-skipping of the flat plate is carried out,and the influence of the speed,pitch angle and water-entry angle on the kinematic characteristics is studied.The trajectory and the change of the speed,acceleration and pitch angle of the flat plate after touching the water under different motion parameters are analyzed.The influence of the motion parameters on the skipping motion of the plate and the motion parameters which are beneficial to the skipping motion of the plate and keep the posture are obtained.Based on the high pressure gas power,a test platform is designed and built for the water-skipping movement of complex moving object.Through the high-speed image acquisition system,the image data of the complex configuration moving object is obtained,which can be processed to get the trajectory.In this paper,the trajectory and posture changes in the process of skipping are analyzed,and the influence of pitch angle and other motion parameters as well as the bottom configuration of the model on the kinematic characteristics of the moving object is obtained.The motion parameters and configuration design that are more conducive to skip and maintain the attitude stability in the test are given.