| After the closure of the Meishan Waterway at Beilun,Ningbo,a semi enclosed artificial beach is formed.And the water area is large with limited discharge from the tides,resulting in poor seawater flow and easy water pollution.For this reason,artificial current generation can be carried out by arranging three platforms and five jets on each platform in the semi enclosed sea area.The water circulation in the semi enclosed sea area can be accelerated.This article conducts numerical simulation research and experimental verification on the artificial flow in the water area.Firstly,numerical simulation analysis was conducted on the hydrodynamic state of the Meishan Bay water area,after the closure of the reclamation project.Using turbulence model combined with FAVOR method,a three-dimensional water body model and hydrodynamic model are established.And CFD technology to establish a full-scale simulation model is used.Secondly,in order to improve the accuracy of the model and accelerate convergence speed,solve the problem of transition between smaller size jets and larger area grids in the hydrodynamic model,overlapping grid method and proportional modeling method are combined in the model.Then,numerical simulations were conducted on four artificial flow conditions: single platform operation,5 jets generators per platform,4 jets generators per platform,and 3 jets generators per platform.Finally,different measurement points were selected for actual measurement,and the current velocity and direction at different measurement points under different working conditions were measured.And the simulation results with the measured results are compared and verified to analyze the flow field characteristics and flow generation effect of large-scale artificial flow generation areas.Through quantitative analysis of the impact of artificial flow on the flow velocity of water in semi enclosed waters,the following conclusions are drawn: The numerical simulation results of ocean current velocity are slightly larger than the actual sea test results,with an average error of about 15%,mainly due to the lack of consideration of wind and terrain effects in the numerical calculation process;Due to factors such as wind force and seabed topography during on-site measurement,the measured flow velocity at the measuring point is significantly smaller than the numerical simulation flow velocity value.And the direction of the measured flow velocity is more unstable.The shape and flow direction of the central jet belt shown in the numerical simulation flow velocity cloud map are basically consistent with the measured shape and flow direction of the jet belt.As the number of jets increases,the water flow velocity results at the same measuring point gradually increase.The comparison between multiple sets of numerical simulation results and actual sea test results shows that the flow field and streamline of the measured and simulated results are basically consistent.The research shows that the calculated results of numerical simulation are highly consistent with the measured results.This numerical simulation method can be used to study the flow field characteristics of a large range of artificial flow areas.The scheme of accelerating water circulation by using jet devices can be analyzed and optimized.Finally,a large range of water circulation can be realized to achieve the purpose of improving hydrodynamic conditions.This study has important guiding significance for the engineering practice of artificial flow generation in semi enclosed waters. |
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