基于小扰动理论的微弯河岸沿线扰动压力分布

摘要

In order to reveal the discipline and the main influence factor of disturbed pressure distribution along sinuous bankline,the small disturbance theory was used to linearize the 2D shallow water equations and the boundary conditions.Analytic expressions of disturbed pressure along sinusoidal curved bankline had been derived.A sensitivity analysis of influence factors was also presented.The pressure expressions and sensitivity analysis show that the disturbed pressure along the slightly curved bankline follows sinusoidal distribution.The crest and trough values of disturbed pressure appear at the maximum curvature locations of concave and convex bank,respectively.The bank amplitude-to-wavelength ratio a/λ is found to be the main factor of pressure variation in subcritical flow.The derived results can be used to estimate the boundary condition of stream-subsurface exchange in riparian zones,which is helpful to the further study on lateral hyporheic exchange and hydrodynamics in riparian areas.%为揭示微弯河岸沿线的扰动压力分布规律及主要影响因素,以水流运动的二维浅水方程为基础,运用小扰动理论对基本方程及边界条件进行线性化处理,推导正弦型微弯河岸缓流情况下的扰动压力分布公式,并进行影响因素的敏感性分析.压力分布的解析解与影响因素的敏感性分析表明,在缓流条件下,正弦型微弯河岸的扰动压力分布呈正弦曲线变化,扰动压力的峰值和谷值分别出现在凹岸和凸岸的最大曲率位置,弯曲河岸的振幅与波长比a/λ是影响其沿线压力分布的主要因素.研究成果可用于估算河流地表水与河岸地下水交换的边界条件,将有利于河岸侧向潜流交换机理及河岸带相关研究的进一步开展.