Study On Hydrodynamic Characteristics And Structural Optimization Of Artificial Reef Based On Numerical Simulation

The construction of marine ranching is an important way to protect the sustainable development of marine fishery resources,and the placement of artificial reefs in the target sea area is an important means of modern marine ranching.How to effectively play the effect of artificial reefs has become the key link of project construction.Based on different artificial reef model as the research object,the numerical simulation method,using Fluent software for structure side length is 3 m’s HUT,framework,cross airfoils,six shuttle table type,cubic diagonal surface opening type and the optimized four trapezoid table reefs in four different kinds to flow velocity and flow angle of attack of the flow field characteristics and stability are analyzed in numerical simulation.Based on reefs range and stability characteristics of flow field in space,select upwelling,back eddy current volume,resistance and overturning moment as evaluation index,the first time from the angle of system engineering,this paper puts forward a base on order relation entropy method effect comprehensive evaluation method for the construction of artificial reefs and provide theoretical reference for construction of artificial reefs.Through numerical study and analysis,the results show that :(1)under the same other conditions,the upwelling volume and back vortex volume are less affected by incoming flow velocity,and the reef can produce relatively stable flow field effect in the sea area with high tidal current velocity and the sea area with low tidal current velocity.The flow field scale of artificial reef increases with the increase of flow attack angle.In order to optimize the flow field effect,the flow field volume in the upwelling and back vortex regions can be greatly increased by setting a cross-shaped diversion plate inside the reef body,and the flow field efficiency can be effectively improved.(2)The resistance and overturning moment of four trapezoidal platform reef are less than those of the cubic diagonal open reef,indicating that the larger the tilt Angle of the flow surface of the reef,the smaller the force on the reef,and the higher the stability of the reef;When the inflow velocity increases,the resistance value and overturning moment of the reef body gradually increase.In order to avoid instability of the artificial reef,the artificial reef should be placed in the sea area with low tide velocity.There is a strong correlation between the angle of attack and the stability of reef.Reef model resistance is 1.35 times,overturning moment is 1.33 times.(3)The comprehensive evaluation value of artificial reefs with internal guide plates is greater than that of reefs with internal hollow structure,indicating that setting guide plates helps to achieve better construction effect;A and B trapezoidal platforms have better comprehensive effect,that is,when the length of the upper and bottom prisms is 2 m～2.5 m,the trapezoidal platform reef can obtain better comprehensive construction effect.For the trapezoidal platform reef with internal diversion plate,the optimal construction effect can be obtained when the angle of attack is between 30° and45°.Therefore,the angle of attack should be controlled between 30° and 45° when the artificial reef is actually placed.