Resistance Characteristics of High-Density Net Influenced by Biological Adhesion
In offshore farming environment,the cage net is prone to be damaged due to great resistance caused by biological adhesion.In order to understand the resistance characteristics and flow field changes of cage net under biological adhesion in offshore farming environment,we analyzed the hydrodynamic characteristics of single piece net and whole net with different degrees of biological adhesion by using a porous medium model based on CFD method.In this study,we first verified the feasibility of simulating net with porous media model,then analyzed the flow field and resistance changes of single net with different biological attachment degrees,and finally compared the flow field distribution and resistance changes of the whole cage under different biological attachment degrees.We found that with the increase of net density,the velocity attenuation behind the cage becomes more and more obvious,which is not conducive to regional water exchange.At the same time,the velocity at the bottom of the cage increased more and more obvious,and the erosion of the seabed below the cage was gradually enhanced,which is not conducive to the stability of the cage.The changes of flow field and total resistance inside the net were mainly affected by the density of the net while the net length has little effect on the change of flow field and total resistance inside the net.The net resistance increased first slowly and then quickly and then slowly with the increase of the density of the net.The results showed that the biological attachment has a great influence on the flow field around the net and the resistance of the net,which will seriously harm the safety of the net cage.
netbiological adhesionhigh densityporous media modelresistance characteristics
万方数据
维普
