Dynamics Of Water Entry For Semi-closed Cylindrical Shell Of Self-floating

Semi-closed cylindrical shell is a kind of thin-walled cylindrical shell structurewith one side closed and the other side open. In this paper, a semi-closed cylindricalshell structure model is designed, which is floated on the vertical water-entryphenomena freely with the closed side up, the open side down. This thesis is basedon numerical simulation and experimental study to analyze the water-entryphenomena, discuss the kinematic characteristic, dynamic characteristic and thefeatures of multiphase flow field. Examines the effects of several key parameters onthe vertical water-entry freely physics of Semi-closed cylindrical shell. To get thefeature of the process, we compare it with cylindrical shell whose two sides areclosed on water-entry process.Firstly, we introduce the control equation of the multiphase fluid dynamics andthe numerical solution method briefly. Then we analyze the effectiveness of thenumerical solution. We optimize the model by the floating condition and thestability condition.Secondly, we use Fluent software to analyze water enter phenomena ofSemi-closed cylindrical shell through the numerical method. We can get the law ofcentroid movement, the law of velocity time-varying, the flow field force, thepressure of the shell, the law of the cavity development, and the vibration process ofthe air spring in the cavity. Then we can analyze the model water-entry progressdeeply and give the reasonable explanation to all kinds of phenomenon of theprocess.Thirdly, we make an experiment for vertical water-entry process of thesemi-closed cylindrical shell model by the high-speed video technology to get thelaw of translation and the rotation and the law of the water-entry cavitydevelopment.At last, we analyze the water-entry phenomena based on numerical simulationand experimental study and get the law of centroid movement, the load of the modeland the law of the cavity development under different speed or the differentfloating-weight ratio condition. We compare characteristic of the semi-closedcylindrical shell model with characteristic of the closed cylindrical shell model fromthe aspect of the water-entry movement law, impact into the water, the law of thewater-entry cavity development and the stability of water-entry, then we get thefeature of the semi-closed cylindrical shell model on water-entry phenomena further.