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在床面上铺设不透水防渗板是对水下管道局部冲刷进行防护的一种新方法,为加深对这种防护措施的了解,首先应用有限体积法和VOF方法对恒定流作用下水下管道局部绕流流场进行了数值模拟分析,得到了考虑水面变化时的管线周围床面压力分布情况,讨论了水深、单向防渗板及双向防渗板长度对压差的影响.在此基础上,基于层流模型和多孔介质模型对管道周围海床的渗流场进行了数值计算.分析了防渗板长度对水力梯度分布的影响,并对防渗板的临界长度进行了研究分析.结果显示,计算结果与前人试验结果基本符合.水深小于5.00D时,水深对于床面压力的影响较为显著;单向防渗板和双向防渗板两端压差均随着防渗板长度的增加而减小,且压差变化值较为接近;防渗板长度的增加,延长了渗流的渗透路径,减小了渗流区的水力梯度,有效地避免了管涌的发生;防渗板的临界长度随着水深的增加而逐渐减小,当水深大于4.00D时,水深对于临界长度的影响较小;在相同水深情况下,临界长度随无量纲流动参数的增加而逐渐增大.
Impervious impermeable board is a new way to protect local scour of underwater pipeline. In order to deepen the understanding of this protective measure, the finite volume method and the VOF method are applied to the underwater pipeline The numerical simulation of partial flow field is carried out and the pressure distribution around the pipeline considering the water surface change is obtained. The effects of water depth, unidirectional anti-seepage plate and the length of the bi-directional anti-seepage plate on the pressure drop are discussed. , The seepage field of the seabed around the pipeline is numerically calculated based on the laminar flow model and the porous media model.The influence of the seepage prevention plate length on the hydraulic gradient distribution is analyzed and the critical length of the seepage prevention plate is analyzed and analyzed.Results The results show that the calculated results are in good agreement with those of the predecessors.When the water depth is less than 5.00D, the influence of water depth on the bed pressure is significant. Increase and decrease, and the pressure difference is close to the value; Increasing the length of anti-seepage plate, extending the percolation path of seepage, reducing the hydraulic gradient of seepage area, effectively avoiding the occurrence of pipe flooding; Boundary length with increasing water depth decreases, when the water depth is greater than 4.00D, the critical length smaller depth effect; at the same water depth, with no increase in critical length dimensionless flow parameters gradually increases.