波浪作用下沙纹床面形态及底摩阻系数研究  

Study on wave-induced ripple characteristics and bottom friction factors

作　　者：肖千璐 李瑞杰[1,2] 王梅菊[1] 

机构地区：[1]河海大学海岸灾害及防护教育部重点实验室,江苏南京210098 [2]河海大学港口海岸与近海工程学院,江苏南京210098

出　　处：《水运工程》2017年第5期12-18,共7页Port & Waterway Engineering

基　　金：江苏省普通高校研究生科研创新计划项目(KYZZ15_0143)

摘　　要：波浪作用形成的沙纹在近海区域普遍存在,准确预测沙纹床面形态并计算对应的底摩阻系数是研究近岸波浪变形、泥沙输运及岸滩演变的基础。利用国外公开发表的室内试验和现场观测数据对已有计算沙纹形态的典型公式进行分析评价。考虑床面形态与水流条件的互相适应,提出新的平衡状态下沙纹长度、高度及波陡计算公式;引入临界Shields参数判别函数来考虑底床泥沙运动状态对沙纹形态的影响;通过理论推导得到波浪摩阻系数计算公式,并利用沙纹形态计算公式改进粗糙高度的计算方法。结果表明,提出的沙纹形态计算公式能够较好地刻画不同底沙运动状态下沙纹床面几何特征,临界Shields参数对于沙纹形态的计算具有重要影响;新得到的沙纹长度和高度公式可以有效地应用于波浪摩阻系数计算。The ripples under the action of waves are prevalent in the offshore area.The accurate prediction of the ripple characteristics and bottom friction factors is the foundation of the research on the wave deformation, sediment transport and the evolution of shoreline. The formulas commonly used for the calculation of the wave-induced ripples are analyzed and evaluated by using the published experimental data from the laboratory experiment and the field observation.The coordinated property of the bed form and the flow condition is considered, and a new prediction method is proposed to calculate the ripple equilibrium geometry such as length, height and steepness.The discriminant function including the wave critical Shields parameters is introduced to take the effect of the bed load transport into account.The formula of wave friction factor is derived theoretically, and the estimation of roughness height is improved by the sand ripples formulas. The results show that the proposed formulas can give a better description of the ripple geometrical characteristics when the bed load sediment move in different state.The critical Shields parameters influence greatly on the calculation ripple geometry. Moreover, the new ripple prediction can be used to calculate bottom friction factors efficiently.

关 键 词：沙纹 波浪 床面形态 临界Shields参数 底摩阻系数 

分 类 号：U652[交通运输工程—港口、海岸及近海工程]