Numerical Simulation Research About The Interaction Between Plane Mesh And Water Flow Based On SPH Method

In recent years, due to population growth, we demand for aquatic products increasingly, which make offshore aquatic resources depleted gradually. Coupled with overfishing and the impact of irrational development and other factors, the coastal marine environment is gradually deteriorated, the pollution and disease problems in aquaculture area have become more prominent, which result in the declined quality of farmed fish, and the improved mortality rates. For this reason, we need to transfer aquaculture cage from the inner bay、offshore to open sea or deep sea It is an inevitable trend in the development of cage aquaculture to seek superior breeding environment and high quality of aquaculture products. In this situation the deep water breeding cages come into being. As an important part of the deep-water aquaculture cages, net is one of the most critical system components in the whole cage, which can not only provide space for the growth of farmed fish, but also prevent the escape of fish and predators’ attack. So the feature of soft net is that the net may easily move deformation under external loads. With the increasement of the flow velocity, the cages will have larger volume loss, thus it will affect the normal growth of farmed fish. Therefore, It has important practical significance to study the net’s movement distortion and overall force under the flow, for which is reference to in-depth understand of the flow resistance characteristics of the cages and to choose cage zone、cage materials. In the course of cage aquaculture, fish tank water flow and growth is closely related to the size of the tank water velocity,which determines the switch speed of the water inside the cage, and has impact on the environment inside the water quality significantly, so the net flow reduct actions research is a major concern.in this article, It uses the basic principle of SPH method and lumped mass method,Compiles Fortran program language, and also uses of numerical simulation method to study hydrodynamic characteristics about the interaction between net and different flow rates, in order to get the results between computer simulation and experimental value. The results show that: numerical simulation about flow flume and net interaction in the three dimensional sink, where the measuring point velocity around net flow field with the experimental error is less than 10%, the net overall force between numerical simulation value and experiment value ??error is less than3%. although there is no test result to compare, deformed shape net is also write in this article.There are research papers consisting of five parts: The first section is an introduction, the paper introduces the research background, and domestic and foreign research progress on the net hydrodynamic characteristics ender water flow; The second section introduce the basic idea and the basic theory of ??SPH method;The third section applies SPH method to simulate Poiseuille flow simulation, the results compare with the series solution and which reach the conclusion that SPH method is feasible and accuracy to simulate two dimensional uniflow; The fourth section simulate three dimensional uniform flow in the tank by using two kinds of SPH numerical simulation methods, the result is that apply SPH method with space physical stress is more in line with the actual sink flow process; The fifth section is the numerical simulation about the interaction between plane net and flow interaction based on SPH method, study and meanwhile show that the flow field form around the plane net, net total force size and deformed shape at each time, and let each part of the simulation results to compare with the test results, and analyze the cause of the error.The appendix section is public research programs written according to the study issue,the key technical solution is accomplished by writing the relevant procedures, the purpose of this program is as a reference for open the back of researchers continuing to study related subjects. Finally, the main research results obtained are summarized in this article, at the same time we prospect hydrodynamic characteristics of the research about plane net, circular net cages, clothing and so on.