平面网衣在水流作用下的受力和变形特性数值模拟研究

Numerical simulation of the force and deformation of submerged plane nets in current

  • 摘要: 基于集中质量点法和牛顿第二定律,建立了网衣在水流作用下的受力和运动响应数学模型。采用计算机数值模拟方法,研究了水流作用下网衣的动态变形情况以及网衣受力平衡后的空间分布形状。在2种配重(GW1=4.12 N、GW2=16.38 N)和6种流速(U=0.17、0.22、0.28、0.33、0.39和0.44 m·s-1)条件下对网衣稳定后沿水流方向的总水流力、网衣底端的水平及垂直位移进行了数值计算。计算结果表明,配重及流速大小对网衣受力和变形特性具有较大的影响。随着水流速度的增大,网衣在水流作用下的运动变形加剧,且当配重增大时,网衣变形减小,网衣受力随流速的变化增幅明显加快。为了验证模型的正确性和有效性,文章还将数值模拟结果与前人的试验结果进行了比较,效果良好。

     

    Abstract: Based on the lumped mass method and Newton′s second law, the numerical model of the force and movement response for fishing nets in current was set up, and then the dynamic deformation and the equilibrium configuration of the plane net in current along the positive direction of x-axis were studied by means of computer numerical simulation method. In this paper, under the conditions of two weight modes (GW1=4.12 N, GW2=16.38 N) and six current velocities (U=0.17, 0.22, 0.28, 0.33, 0.39 and 0.44 m·s-1), the total drag force in the forward flow and the horizontal and vertical displacements of the net bottom were calculated after the plane net getting equilibrium in current. The calculated results showed that the influences of weight system and current velocity on the characteristics of drag force and deformation of plane net are significant. With the increase of flow velocity, the motion deformation of the plane net in current was intensified obviously. Moreover, when the weight increased, the deformation of the net decreased accordingly, and the enhancement of the total drag force accelerated apparently with the flow velocity increasing. Simulated results consisted well with other investigator′s experimental data, which verified the accuracy and efficiency of the model.

     

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