| The multi-layer slotted barrier is a new type of environmental wave dissipation structure,which is mainly used in small yacht marinas.The wave dissipation structure is composed of multi-layer slotted walls with a certain spacing,and has many outstanding advantages compared with the traditional wave dissipation structures such as breakwaters.Since the structure is slotted,the water body is allowed to exchange freely on both sides of the structure,and the ecological environment is protected.The structure is simple,which is convenient for construction and installation.The floor area is small,which can effectively improve the internal space of the port and wharf,and the project cost is low.At present,there are few studies on this structural form,and it is of practical significance to carry out the research and analysis on the wave dissipation effect and hydrodynamics characteristics of multi-layer slotted barrier under the action of regular waves for the practical application of engineering.In this paper,the numerical simulation is adopted.Based on the open source software Open FOAM,the numerical wave flume is established by using the finite volume method and the fluid volume method.The validity and accuracy of the numerical wave flume established in this paper are verified by comparing the experimental data of the physical model of the interaction between the baffle permeable structure and the slotted barrier.Numerical wave flume can effectively simulate the wave surface change,wave dynamic pressure and flow field information under the action of regular waves and multi-layer slotted barriers.Based on the mathematical model,the wave dissipation effect of multi-layer slotted barrier is studied.The transmission and reflection coefficient and energy loss coefficient of slotted barrier under different wave elements,different spacing,different layers and different porosity are calculated.The changes of transmission and reflection coefficient and energy loss coefficient with relative water depth h/L and relative wave height h/H are analyzed.The calculation results show that the multi-layer slotted barrier has good wave dissipation effect;with the increase of relative wave height H/h,the reflection coefficient and energy loss coefficient increase,and the transmission coefficient decreases.With the increase in the number of layers of multi-layer slotted barriers,the reflection coefficient changes little,the transmission coefficient decreases,and the energy loss coefficient increases.When the number of layers of slotted barriers is greater than 5,the continuous increase in the number of layers will not further reduce the reflection coefficient,the structure exhibits strong wave energy attenuation characteristics.In order to further study the wave dissipation mechanism of slotted barrier,the flow field vector diagram,streamline diagram,wave energy flow transfer process and wave dynamic pressure distribution around the structure are analyzed.In the process of water passing through the slotted barrier,there are different numbers and sizes of flow vortices generated around and inside the structure,and the internal waves of the structure are broken to varying degrees.These phenomena are the main mechanism of wave dissipation in the slotted barrier.When the wave passes through the slotted barrier,the wave energy flux of different sections gradually changes in the transmission process from forward to backward: with the increase of the number of slotted barrier layers,the back wave of the structure gradually decreases to the Wave energy flux,and the wave dissipation ability gradually increases.When the number of slotted barrier layers n is 6,the maximum attenuation of wave energy flux can be 93%.With the increase of the porosity of the structure,the wave passing through the structure increases,and the back wave energy flux of the slotted barrier gradually increases,and the wave dissipation effect of the structure decreases.The analysis of wave dynamic pressure at different positions of the slotted barrier shows that the wave dynamic pressure of the vertical slotted barrier is larger in the side of the wave front,and gradually decreases from the side of the wave front to the rear of the slotted barrier.The wave dynamic pressure acting on the slotted barrier gradually decreases from the surface to the bottom;Generally,the wave dynamic pressure decreases with the increase of relative water depth h/L,and the change of relative wave height H/h has little effect on the wave dynamic pressure.With the increase of the number of slot barrier layers,the wave dynamic pressure acting on the last layer of the slot barrier decreases gradually.With the increase of the porosity of the structure,the wave dynamic pressure acting on the slot barrier decreases gradually.The change of the flow field around the structure determines the change of the wave dynamic pressure on the slotted barrier. |
