规则波对沙坝沟槽地形上裂流特性影响的数值研究

Numerical Study on the Formation Characteristics of Rip Current in Topographic of Bar with Rip Channels Induced by Regular Waves

针对理想沙坝沟槽型地形,采用Boussinesq相位解析水动力模型模拟了沙坝沟槽地形下裂流的形成过程,着重分析了沙坝沟槽地形对入射波波高、周期、浪向、地形粗糙程度的敏感性.结果表明裂流的强度与入射波波高、入射波周期成正比;与入射波角度和地形粗糙程度成反比.波高及周期的增大会在沙坝靠岸侧堆积大量的水体使得该处的流场分布变得复杂.当入射波的角度增大时离岸流将转换为沿岸流,其强度也将减小.地形摩阻系数的增大使得裂流的延伸距离及沟槽处的流速减小,但其分布宽度变大.以上研究结果对深入了解沿岸沙坝沟槽地形的裂流形成机制及防灾减灾具有一定的参考意义.

Based on the rip channel topography of an idealized bar,a Boussinesq-type phase-resolved hydrodynamic model is utilized to simulate the generation of rip currents in topographic of bar.Attention is focused on the analysis of the sensitivity of rip currents to wave height,period,wave incidence direction,and bottom friction.The results indicate that the intensity of rip currents is directly proportional to the height and period of the incident waves,but inversely proportional to the degree of friction between the angle and the terrain.The increase in wave height and period leads to the accumulation of water on the shore side of the bar,resulting in complex current field distribution.When the angle of the incident wave increases,offshore currents are converted into alongshore currents,leading to a decrease of the intensity.Moreover,an increase in the topographic friction coefficient results in a decrease in the extension distance of the rip currents and the flow velocity at the channel,but an increase in the width of the rip currents.This study provides profound insights into the formation mechanism of rip currents in the gully terrain of longshore bars,contributing to the disaster prevention and reduction.