Author(s): Wen-Chang Yang; Robert R. Hwang; Chih-Min Hsieh; Yih-Ferng Peng
Linked Author(s):
Keywords: pair of submerged double obstacles; Vortex generation; Spatial harmonic evolution
Abstract: The purpose of the present study is to develop a numerical model to investigate the effects and characteristics as water waves propagate over a pair of impermeable submerged obstacles. The mathematic model is formulated by coupling solutions of the Navier-Stokes equations and transport equations defined by VOF method to accurately capture the water surface elevation. Based on a staggered computational mesh, a numerical algorithm is employed explicitly with a predictor-corrector procedure of pressure and velocity field. The validation of the proposed model shows good agreements of comparisons between obtained numerical results and experimental results and ensures the established model well performance. In terms of spatial harmonic evolutions of various cases, it is noted that present fluctuating mode of harmonic amplitudes exists at upstream and the gap between obstacles. It implies that the nonlinearity of propagating waves becomes stronger than initial wave in such area, and it reveals in the wave profiles appearing much steeper than initial wave profiles. The fluctuating harmonic amplitudes vary with distances of gaps. The vortices play an important role just like a water column wall as fully development on enhancing wave reflection The maximum reflection occurs in cases with gap S/L= 3/8 and S/L= 7/8 in this study.
Year: 2005