Dynamic response of soft poroelastic bed to linear water waves - A boundary layer correction approach

Abstract

According to Chen et al. (Journal of Engineering Mechanics, ASCE 1997; 123(10):1041-1049.) a boundary layer exists within the porous bed and near the homogeneous-water/porous-bed interface when oscillatory water waves propagate over a soft poroelastic bed. This boundary layer makes the evaluation of the second kind of longitudinal wave inside the soft poroelastic bed very inaccurate. In this study, the boundary layer correction approach for the poroelastic bed is applied to the boundary value problem of linear oscillatory water waves propagating over a soft poroelastic bed. After the analyses of length scale and order of magnitude of physical variables are done, a perturbation expansion for the boundary layer correction approach based on two small parameters is proposed and solved. The solutions are carried out for the first and third kind of waves throughout the entire domain. The second kind of wave which disappears outside the boundary layer is solved systematically inside the boundary layer. The results are compared with the linear wave solutions of Huang and Song (Journal of Engineering Mechanics, ASCE 1993; 119:1003-1020.) to confirm the validity. Moreover, a simplified boundary layer correction formulation which is expected to be very useful in numerical computation is also proposed. © 2001 John Wiley & Sons, Ltd.