波浪作用下沙纹上含沙量的时变特征  

Time-dependent nature of suspended sediment concentration over ripples due to waves and wave groups

作　　者：吴国强[1] 邹志利[1] 张海飞[1] 

机构地区：[1]大连理工大学海岸和近海工程国家重点实验室,辽宁大连116024

出　　处：《泥沙研究》2013年第2期16-24,共9页Journal of Sediment Research

基　　金：国家自然科学基金(51079024);国家创新群体基金(51221961)

摘　　要：对规则波、不规则波和波群作用下沙纹峰上悬移质含沙量与波浪形态的关系进行了实验研究。结果表明:在规则波情况下的波峰和波谷时刻,含沙量都出现了相应的峰值,但波谷时刻对应的峰值要大于波峰时刻的峰值;在波群情况下,含沙量对于波浪的响应主要集中在波群周期上,在短波频率上所占分量很小。含沙量的时间平均值随着调制系数的增大而减小,但其波动部分的幅值是随着调制系数的增大而增大;不规则波情况下只在大波经过沙纹峰上的时刻,才有明显的泥沙悬移现象,含沙量主要是响应于波列中波群出现的频率,这表现在含沙量能量谱的峰值对应于波浪包络能量谱的峰值。实验结果也显示了波群和不规则波波高变化导致的泥沙悬移运动的滞后现象。The experimental study of the temporal characteristics of suspended sediment over wave ripples un- der the actions of regular waves, wave groups and irregular waves was performed. Different modulations were taken for wave groups in order to investigate the effect of wave height variation. The results are as follows. For regular waves the peaks of suspended sediment concentration corresponding to wave crests are higher than that corresponding to wave troughs; for wave groups the sediment suspension event has the basic oscillating fre- quency as same as that of wave group, instead of that of short wave, and the strength of this oscillating compo- nent increases with increasing amplitude modulation, but the corresponding mean component sediment concen- tration decreases; for irregular waves, the basic oscillating frequency is also corresponding to wave group fre- quency, but the time lag is observed for the time series of sediment concentration with respect to the free sur- face elevation. By the examination of the results of wave group cases, the reason is the result of wave height variation of irregular waves.

关 键 词：波浪 沙纹 泥沙悬移 波群 调制系数 

分 类 号：TV149.2[水利工程—水力学及河流动力学]