Experimental Study On The Hydrodynamic Characteristics Of The Four-prismatic Permeable Frame

The coastal protection project is an important part of river regulation,and it has an important effect on the effective prevention of coastal erosion and control of river potential.Permeable frame is a collection of ecological protection,flood control in one of the "hydrophilic" type of protective structure.Combining with the concept of reef and the application of permeable frame,a new type of beach protection structure-four-prismaic permeable frame is proposed to carry out the experimental study of water flow characteristics.The principle of this method is discussed as a suitability and protective effect of the shore-beach protection structure.The main conclusions are as follows:(1)The flow characteristics of the four-prismic permeable frame was carried out.The velocity of water flow in the permeable frame was measured with the flow velocity profiler(ADCP).The influence of different overhead rates,laying length and laying interval on the flow structure was analyzed.It is found that the permeable frame with four-sided platform will change the distribution of velocity,turbulence intensity and Reynolds stress,and the flow velocity distribution has stratification characteristics.The turbulence intensity and the Reynolds stress distribution appear inflexion point.The overhead rate and arrangement interval decrease and the layout length increases,The flow velocity decreases and the flow velocity in the transitional layer and the surface layer increases.The turbulence intensity and the location of inflexion point of Reynolds stress vary with different heading rates.(2)This paper studies the protective effect of the four-prismatic permeable frame from the angle of deceleration dissipation effect,and obtains the relative parameters of the practical engineering application of the four-prismatic permeable frame.It was found that the overhead rate decreased,the relative layout length increased,the relative layout separation decreased,the effect of the deceleration of the four-sided frame was better.The null rate is 4.202,and the relative layout length is 4.33,which is the best combination of deceleration effect,and the initial realization is that when the four edges of the frame are not larger than 1.0 L,there is a good deceleration effect.