Experimental Study On The Oceanic Internal Waves Reduction Facility

The ocean contains a wealth of resources.People paid more and more attention to the exploitation and utilization of the oceans with the rapid development and expansion of the world.As an important phenomenon of natural movement in the ocean,internal solitary waves(ISWs)make a great contribution to the exchange of energy in the ocean,but it also brings a great influence and considerable harm to the marine engineering structure.Therefore,it is of great economic significance to study the reduction of internal solitary waves and its corresponding defense mechanism for the safety of marine structures.On the basis of reviewing and analyzing the previous researches on internal solitary waves,this paper studied the force acting on the thin plate structure and the attenuation effect of ISWs by means of numerical simulation and physical experiment aiming at reducing internal waves.The main research contents and the results are as follows:(1)This paper proposes a method of decreasing the ISWs using the "net" by studying the attenuation method of similar wave and the attenuation law of internal wave.The attenuation of internal waves during propagation is mainly caused by shear instability and convection instability,so we need to set the barrier for the propagation of the internal structure of interference in its communication process,while taking the idea of reflection attenuation for its low frequency,long –period and strong diffraction ability.So we put forward a practical method of using the net combined with the marine actual situation and the practices of reducing acoustic wave and surface wave.(2)The force of thin plate becomes larger with the increase of ISWs' amplitude by taking the numerical simulation using Fluent based on the conclusion of effects on the piles and the submerged body caused by the ISWs;At the same time,the force changes of the plate is nonlinear when the original internal wave encounters different angles under the same amplitude,it will mutate in 27°and 45°,while reaches a maximum in 27°.(3)Do the physical experiment of ISWs' attenuation in the two dimensional flume basing above.The experiment changes the angles and the piles of the net and gets the conclusion that the net has the great effects in reduction of ISWs by the statistics of the changes after the interactions of net and ISWs.The effects change by changing the angle of the net for single net,and it reaches the best in 27°;two layer‘s net has better in reducing ISWs of large amplitude,but the space between them should not be too large,or the ISWs will absorb the energy in the flow and reduce the effect of the first layer net.