Experimental Study On Hydrodynamic Characteristics Of Net Cage Under Different Submergence Depth

In recent years,with the expansion of the inshore aquaculture industries,inshore water pollution and fish disease become more severe.Ocean aquaculture has become an inevitable choice.Technical solution of wind wave and flow resistance are the main problems of ocean aquaculture.Lifting net cage is widely used in the deep sea.Lifting net cage has floating state and diving state.The net cage can dive to avoid storms when the harsh sea condition coming.The study of the hydrodynamic characteristics of the cage under different dive depth is the basic research necessary to solve this technology.In our country,there is less research on lifting net cage.There is less theoretical basis for the design and selection of lifting net cage.In this paper,the experimental model test is used to study the hydrodynamic characteristics of the cage.This experiment was carried out in the State Key Laboratory of Coastal and Offshore Engineering of Dalian University of Technology.This experiment included the making of cage flouting frame,net,anchor rope and the design of the experiment conditions.Hydrodynamic characteristics of the net cage under the action of wave,single current and the combination of wave and current are simulated by the method of model experiment.The contents of the dissertation are mainly composed of four parts.In the first chapter,the background and significance of this research is introduced,and give the advance in the hydrodynamic characteristics of the net cage.Based on the previous research,the target and content of this study are presented.In the second chapter,a series of physical model tests are performed,in which the physical model of lifting net cage is designed according the material parameters and geometrical of the most common used net cage and the physical parameter of the physical tank.The third chapter studies the hydrodynamic characteristics of the lifting net cage under wave action.In the fourth chapter,the hydrodynamic characteristics of the lifting the cage under the action of single current and the combination of wave and current are studied.At the end of the paper,the achievements of this study are summarized,and the further study and prospects are given.