消浪导流型人工鱼礁的消波性能研究

Research on the Wave Dissipation Performance of High Wave-dissipating and Low Flow-retarding Artificial Reefs

为探究不同礁体数量、不同单位鱼礁礁距和不同开口比对消浪导流型人工鱼礁消波性能的影响,该文采用计算流体力学方法(computational fluid dynamics,CFD),利用大涡模拟(LES)对不同礁体组合进行三维波浪数值模拟,并以波浪透射系数和波能耗散率等指标分析了消波性能;选取消波效果较好的一种礁型增设其内部阻流板等结构,并以上升流体积和背涡流体积等指标为流场效应进行了分析。结果显示,利用FLOW-3D软件造波具有良好的稳定性和持续性。随着鱼礁数量的增加,礁区相对波长的倍数随之增加,波浪透射系数呈现先快速降低后缓慢降低的趋势,其中A4礁体组合的透射系数Kt为0.33,消波效果较好;随着单位鱼礁间距的增大,波浪透射系数呈现先增加后降低直至平稳的趋势。对于顶板而言,随着开口比的增大波浪透射系数逐渐增加;而对于挡板开口而言,礁体在波浪传播方向上的透水性对波浪透射系数变化影响显著。研究表明,礁体数量的增加和单位鱼礁间距的减小对于提升礁体组合的消波效果作用明显;从节约成本和提升消波性能等因素考虑发现,采用顶部封闭和挡板一侧封闭的礁型设置最优。该研究结果可为滨海湿地和“滩涂型”海洋牧场等区域的鱼礁单体优化设计和礁体组合优化布局提供科学依据。

In this paper,in order to investigate the effects of different number of reefs,different reef distance per unit and different opening ratios on the wave dissipation performance of wave deflecting artificial reefs,the computational fluid dynamics(CFD)with large eddy simulation(LES)is used to simulate different reefs,and analyze the wave dissipation performance in terms of wave transmission coefficient and wave energy dissipation rate.The reef type with better wave dissipation effect and added internal flow barrier structure is selected,and its flow field effect in terms of upwelling volume and back eddy volume is analyzed.The results show that the wave creation with FLOW-3D software has good stability and continuity.With the increase of the number of reefs and the increase of the relative wavelength multiplier in the reef area,the wave transmission coefficient shows a trend of rapid decrease and then slow decrease,in which the transmission coefficient K t of A4 reef combination is 0.33 and the wave dissipation effect is good,with the increase of the spacing of unit reef,the wave transmission coefficient shows a trend of increase and then decrease until smooth.As the opening ratio increases,the wave transmission coefficient gradually increases,and for the baffle opening,the permeability of the reef in the wave propagation direction has a significant effect on the change of the wave transmission coefficient.The study shows that the increase of the number of reefs and the decrease of the spacing between reefs has a significant effect on improving the wave dissipation effect of reef combinations,and from the consideration of cost saving and improving the wave dissipation performance,it is found that the reef type with top closure and baffle side closure is optimal.This study can provide scientific basis for the optimal design of reefs and reef combinations in coastal wetlands and"beach-type"marine pastures.