Hydrodynamic characteristics of rectangular submerged breakwaters

In this study, method of separation of variables is applied for investigating two dimensional submerged breakwaters characteristics in an infinite domain. For this purpose, the fluid domain is divided into discrete sub-domains and the velocity potentials are approximated using infinite series of orthogonal functions in each sub-domain. Expression for each region is developed according to boundary conditions except those at common boundaries between the regions. Continuity of pressure and normal velocity, which demonstrate equality of pressure and normal velocity in the boundaries, are satisfied in order to obtain the unknown coefficients in the series. A classical rectangular cross section in finite water depth with four sub-domains is studied in three degrees of freedom e.g. sway, heave and roll. Results are in good agreement with other researches as well as numerical method using boundary element software ANSYS AQWA which is used as a backup in this study. Furthermore, the effects of submergence depth on the exiting forces and the transmission and reflection coefficients are studied. The results show with increasing the submergence depth, reflection coefficient decreases and transmission coefficient increases. Also, it is shown that with enhancing the submergence depth, maximum horizontal and vertical exiting forces decrease and exiting moment increases smoothly.