Optimization study of artificial reef assemblage based on the numerical simulation of flow field

Abstract

Based on the aggregation experiments of feature-reef trough,the occurrence frequency of Sparus Macrocephalus larvae around artificial fish reefs was studied with different structures and at different background velocities.The highest frequency of fish occurrence,space volume of flow velocity of 0.7 times and0.8 times to background were considered as indexes of wake vortex range.The space volume with vertical upwelling velocity 0.1 time and 0.2 time of the upwind horizontal velocity was considered as the index of upwelling range.Based on Fluent with a turbulence model named LES(Large Eddy Simulation),a numerical trough was built and four unit-reef assemblages as an example were adopted to analyze the difference and merits of various assemblages' flow effect.The result showed it was appropriate to place 20-30 unit reefs(cube,3 meters of side length)as a 5-point symmetric mode,and 1-2 times reef distance in reef area,as this could not only bring about synergistic effect of reefs,but also optimize the regulation range of unit-reef.