贝类养殖吊笼水动力特性的实验研究

通过模型实验的方法分别探讨了规则波和均匀流作用下贝类养殖吊笼的水动力特性,并分析了贝类养殖密度对吊笼受力的影响。在波浪作用下,基于莫里森方程,通过最小二乘法计算水动力系数C_d和惯性力系数C_m值;在水流作用下,利用简化莫里森公式反推出C_d值;分析了Kc数、雷诺数Re和养殖密度对C_d和C_m的影响。结果显示:吊笼的运动幅度及受力随着波高、周期及流速的增大而增大;随着贝类养殖密度的增大,吊笼受到的水平力逐渐增大,而吊笼的运动幅度逐渐减小;在波浪效应下,随着Kc数、Re的增大,C_d有略微增大趋势,而C_m则先增大后趋于常数;在水流作用下,C_d值随着雷诺数Re的增大无显著变化;在同一工况下,C_d随着贝类养殖密度的增加而增大,而C_m相应减小。研究表明,本实验得出的吊笼水动力系数可作为计算吊笼波浪力和流阻力时的取值参考。

Experimental study on hydrodynamic characteristics of lantern net for shellfish culture

In this paper,hydrodynamic characteristics of lantern net under regular wave and uniform current are respectively discussed by model test,and the influence of different densities of shellfish on the force of lantern net is analyzed.The hydrodynamic coefficients Cd and Cm are calculated by the least square method based on the Morison equation under wave load;Drag coefficient Cd is calculated using the simplified Morison formula in the effect of current; and the effects of Kc number, Reynolds number and breeding density of shellfish on hydrodynamic coefficients Cd and Cm are analyzed.The results indicate that:The motion amplitude and force of the lantern net increase with the increase of the wave height,period and current velocity;The horizontal force of lantern net increases and the amplitude of the motion decreases as the shellfish breeding density increases;Drag coefficient Cd increases slightly with the Kc number and the Reynolds number increases under wave load, while inertia coefficient Cm increases first and then remains stable; The drag coefficient Cd does not change significantly with the increase of Reynolds number under current action; Under the same conditions, the increase of shellfish breeding density leads to the increase of drag coefficient and decrease of inertia coefficient. The study shows that,the hydrodynamic coefficients for the lantern net obtained from this experiment could be used as reference in the calculation of wave and current loads of lantern nets.