基于单位鱼礁规模的米字型人工鱼礁流场效应定量研究

流场效应是人工鱼礁发挥其生态效应的基础,流场效应强弱受单位鱼礁规模影响,同时是衡量人工鱼礁建设模式优劣与规划人工鱼礁建设模式的重要参考因素,流场体积是表征流场效应强弱的重要指标。本研究基于数值实验方法,分析米字型人工鱼礁在4种布设模式下28种单位鱼礁规模的流场体积变化规律,并建立上升流、背涡流流场体积与人工鱼礁建设规模指标的多元非线性模型。结果表明,单位鱼礁建设一级指标投放量(T_a)、布设间距(L_d)及目标速度比(R_u)与上升流体积分别呈线性、三次函数及幂函数关系,建立上升流体积回归模型为V_u=T_a×(0.002L_r~2-0.055L_r-2.429V_R×R_u+0.011R_u~(-1.833)+0.227L_d+0.437),回归拟合R~2为0.957,相对误差为18.61%。与背涡流体积分别呈幂函数、三次函数及指数函数关系;结合单位鱼礁建设二级指标相对边长(L_r)、容积率(V_R),背涡流体积回归模型为V_b=R_u×(-0.543L_r~2+2.388L_r)–51.779V_R~2+75.045V_R+1.449×10~(-4)T_a×e~(12.049 Ru)+1.620L_d×T_a,回归拟合R~2为0.938,相对误差为10.09%。该流场体积回归模型可用于规划指导均匀布设模式的人工鱼礁建设,为"减量增质提效"的人工鱼礁建设策略提供参考。

Quantitative study on the flow field effect of Mi-zi artificial reefs based on unit reef scale

With the current situation of resource depletion and environmental changes, artificial reefs may be used to promote the fish trapping and breeding to proliferate and conserve fishery resources and restore the ecosystems. The main idea of artificial reef construction was to stimulate the production and transmission of nutrients, sediment size, and primary productivity through the unique flow field generated around the reef, and to proliferate plankton, pelagic swimming organisms, and benthic resources in the form of food supply and habitat transformation. Therefore, the flow field effect of artificial reefs was based on ecological-biological interactions. The strength of the flow field effect is affected by the scale of artificial reef unit. The measurement of the artificial reef construction mode was one of the most important factors for planning the scale of artificial reef construction. The flow field volume was an important indicator to characterize the flow field effect. Based on the numerical experimental method, this paper analyzed the variation of the flow field volume of Mi-zi artificial reefs in 28 kinds of artificial reef scale units in four laying modes, and established the multivariate nonlinear model for the flow field volume of upwelling and back eddy and artificial reef construction model indicators. The results showed that in the primary indicators of artificial reef construction, the throwing amount () and target velocity ratio () and upwelling volume were linear, cubic, and power function, respectively. Combining the relative length (R) of the secondary index to establish the upwelling volume regression model was -0.055_u^-1.833+0.227_b=r)-51.779d× were 0.957 and 0.938, and the relative errors were 18.61% and 10.09%, respectively. The flow field volume regression model can be used to plan the construction of artificial reefs that guide the uniform laying mode, and gradually realize the artificial reef construction strategy of "reducing mass and improving efficiency".