| Geometric parameters such as the structure and shape of artificial reefs will affect the function of artificial reefs,especially the safety of artificial reefs.Moreover,the structure and shape of the artificial reef are closely related to the hydrodynamic force after the reef is released.Therefore,the hydrodynamic performance of artificial reefs has also become one of the main factors that researchers need to consider when evaluating the effectiveness of artificial reef construction.Through the research on the hydrodynamic performance of artificial reefs,the relationship between the structural parameters of artificial reefs and the main force is established,so as to optimize the design of artificial reefs and effectively improve the stability of artificial reefs.In recent years,the research on artificial reefs has mainly focused on the reef body flow field effect,but there are few studies on the stress analysis and stability of artificial reefs.In the stress analysis and physical stability study of artificial reefs,it is important to use the tank model test and numerical simulation to analyze the resistance of the reef under the action of water flow or waves.At present,there is little research on the model test and numerical simulation of artificial fish reefs under different opening ratios and heading angles.Moreover,the hydrodynamic performance of square artificial reefs with hexagonal opening shapes under different parameters such as opening ratio and heading angle is still lacking.Nowadays,numerical simulation is more and more widely used in artificial reef applications,however,there is still a lack of the comparative verification on the numerical simulation and the model test of artificial reef resistance coefficient under different opening ratios and heading angles.Therefore,in order to study the relationship between the drag coefficient,lateral force coefficients of hexagonal opening square artificial reefs and the heading angle,opening ratio,so we use the tank model test to measure the resistance and lateral force of the hexagonal open square artificial reefs under 4 different heading angles??=0°,15°,30°,45°?and 4 opening ratios(?ty=0.0625,0.14,0.25,0.39)were measured,and calculate the drag coefficient and lateral force coefficient to get the reef hydrodynamic changes under different opening ratios and heading angles.And use FLUENT numerical simulation software to numerically simulate the hydrodynamic performance of the same reef model under 4 opening ratios and 4heading angles to verify the applicability of numerical simulation to the hydrodynamic performance of reef model under different heading angles and opening ratios.Research indicates:1.Hexagonal open square reef model resistance Fx?30°?>Fx?45°?>Fx?15°?>Fx?0°??Fx?0.0625?>Fx?0.14?>Fx?0.25?>Fx?0.39?,the lateral force Fy?30°?>Fy?15°?>Fy?45°?>Fy?0°??Fy?0.0625?>Fy?0.14?>Fy?0.25?>Fy?39?;The reef model resistance Fx?30°?is 1.28?1.72 times that of Fx?0°?,and the lateral force Fy?30°?is2.8?11.1 times that of Fy?0°?.The heading angle can have a greater impact on the drag and lateral forces of the reef model.2.Under 4 opening ratios and 4 heading angles,the reef model resistance coefficient CD varies from 0.98 to 1.53?Resistance coefficient CD?30°?>CD?15°?>CD?45°?>CD?0°?,The ratio of resistance coefficient CD?30°?to CD?0°?can be up to1.26 times;Resistance coefficient CD?0.39?>CD?0.25?>CD?0.14?>CD?0.0625??3.Under four opening ratios and four heading angles,the lateral force coefficient CL of the reef model varies from 0.001 to 0.21.Coefficient of lateral force CL?30°?>CL?15°?>CL?45°?>CL?0°?,The lateral force coefficient CL?30°?can be up to 3.5times compared to CL?0°?;Coefficient of lateral force CL?0.0625?>CL?0.14?>CL?0.25?>CL?0.39??4.When?=30°,the force of the lateral force on the reef model cannot be ignored.5.In the numerical simulation of artificial reef and the model test of aqueduct,the resistance coefficient increases with the increase of the opening ratio,which has a clear linear relationship,and the resistance coefficient is the largest when the heading angle?=30°.6.The average error of numerical simulation and model test resistance is 7.43%;the average error of the reef drag coefficient is 5.26%.The correlation coefficients of the resistance of the tank model test and numerical simulation is 0.99,and the correlation coefficients of the resistance coefficient of the tank model test and numerical simulation is 0.80,P<0.001,which has a strong correlation and shows that the numerical simulation method is feasible for the hydrodynamic performance of the reef at different heading angles and opening ratios.7.In this article,checking the stability of the hexagonal open square artificial reef,it is found that the minimum safety factor of anti-drift reef is 3.0,the minimum safety factor of anti-overturning is 6.1,and all are greater than 1.2,which shows that the reefs in the sea area have a velocity of 0.2m/s?1.2m/s,the reefs will not slip and overturn and have a high safety factor.In this paper,the hydrodynamic performance of multiple parameters of hexagonal open square artificial reefs is systematically studied,which provides a reference for the future design and angle of reef structure. |
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