Study On Random Wave Action On Twin-arc-plate Permeable Breakwater

With the development of modern ocean engineering in the direction of deep water,big waves and diversification,in order to ensure the efficient use of marine resources and smooth transportation in coastal areas,it is necessary to build breakwaters to protect port facilities in coastal areas.The traditional gravity breakwater has the disadvantages of difficult construction,high construction cost,difficult to maintain the reasonable development of the marine environment.Therefore,based on the current development background of the marine environment and the existing research theory,it is urgent to find a reasonable and effective coastal protection engineering type.In contrast,permeable breakwater has many advantages,such as low requirements for construction technology and foundation conditions,strong free exchange capacity of water body,and less impact on marine environment.It can adapt to the development trend of modern marine engineering,and is favored and concerned by researchers.At present,flat plate and arc plate are the typical wave dissipating structures.Compared with the flat plate structure,the arc plate structure has more obvious wave breaking effect and better wave dissipation effect.In the real sea environment,the waves generated by the wind are irregular and changeable.Therefore,based on the simulation of the random wave conditions under the actual sea conditions,this paper designs different wave height,plate spacing and diving depth test conditions through the physical model test method,and discusses the influence of different factors on the hydrodynamic characteristics of twin-arc-plate permeable breakwater,The analysis results and main conclusions are as follows:(1)The random waves show strong irregularity and obvious wave impact.Relative wave height and relative submergence have significant effects on the transmission coefficient K_t,reflection coefficient K_r and energy consumption coefficient K_d.With the increase of relative wave height and relative diving depth,the K_t of permeable breakwater will increase.The effect of relative plate spacing on K_t and K_d is not significant,and K_t will decrease to a certain extent with the increase of relative plate width.K_r and K_d decrease with the increase of relative wave height,K_r decreases with the increase of relative plate spacing,and K_r and K_d increase with the increase of relative plate width.(2)The results show that the wave pressure on the different surfaces of the upper and lower arc plates of the twin-arc-plate permeable breakwater and the wave force on the permeable breakwater increase with the increase of the relative wave height;the wave pressure and positive vertical wave force on the permeable breakwater decrease with the increase of the relative plate spacing;the relative submergence h/d has a significant effect on the stress of the permeable breakwater.When h/d increases,the positive pressure on the lower surface of the upper plate and the positive pressure and negative pressure on each surface of the lower plate decrease.When h/d=0,the negative pressure on the lower surface of the upper plate and the positive pressure on the upper surface of the upper plate are larger,and h/d=0.05 is smaller.In the case of 66.7%,when h/d=0.05,the negative pressure on the upper surface of the upper plate is the largest,h/d=0 is in the middle,and h/d=-0.05 is the smallest.The positive horizontal wave force and negative vertical wave force decrease with the increase of h/d.Under the condition of h/d=0.05,the positive vertical wave force on the permeable breakwater is larger,followed by h/d=-0.05,and the minimum under h/d=0.(3)Under different submergence conditions,the flow field changes significantly under the action of random waves and permeable breakwater.The waves climb along the arc surface or fall through the water behind the breakwater.The water body on the left and right sides of the arc plate collides and turns over.With the increase of relative submergence,the turbulence intensity and the ability to hinder waves around the arc plate decrease gradually.