近岸波动平均水动力方程与波浪漫滩边界耦合的理论模型

Incorporation of Swash Zone Boundary Condition into Nearshore Wave-averaged Hydrodynamic Equations

波浪漫滩不仅影响局地水动力,对邻近拍岸浪区的水动力和泥沙运动也有重要影响。但是,近岸波动平均的流场计算尚没有包含波浪漫滩边界的影响。建立包含拍岸浪区的近岸波动平均水动力方程,耦合了波浪漫滩区水流积分的波动平均方程。结果表明,拍岸浪区和波浪漫滩区相互作用机制是水体、动量交换,它们由波浪漫滩区水流的波动平均值或水流积分的波动平均值提供,可以根据波浪漫滩区海滩坡度、海底摩擦及与拍岸浪区交界位置的波高、波向、波周期计算。这些水体和动量交换项可以作为近岸波动平均水动力方程的波浪漫滩边界条件,为考虑波浪漫滩影响的近岸波动平均流场计算提供理论基础。

The swash zone flow is of fundamental importance because of their local effects and their influence on the surf zone dynamics and sediment motion.However,the swash dynamics is not included in the nearshore circulation calculation.Therefore,the wave-averaged hydrodynamic equations in nearshore including surf zone(WAHENS)and the wave-averaged integral hydrodynamic equations in swash zone(WAIHES)were given in the research.Results show that,their interaction mechanisms are the exchanges of mass and momentum,which can be calculated by the wave-averaged integral flow quantities(WAIFQs)or the wave-averaged flow quantities(WAFQs)of WAIHES.WAIFQs and WAFQs are obtained by the parameterizations with the wave height,wave direction and wave period at the interface of swash zone and surf zone together with the beach slope and the friction coefficient in swash zone.The exchanges of mass and momentum are taken as the swash boundary condition incorporated into WAHENS.It provides a theoretical basis for the calculation of the average flow field of the nearshore circulation considering the effect of swash zone.