Assessment of global wave forces and moments on porous vertical barriers in random wave fields

Abstract

Experimental investigations were carried out to assess the global wave forces and wave induced moments on slotted vertical barriers (SVB). Fourty two different wave barrier configurations (5%, 10%, 20%, 30%, 40%, 50% and 60% porosities and 1 to 6 number of slotted walls) were tested in random wave fields of JONSWAP spectra for wide range of significant wave heights and peak periods. It is found that the wave force is very sensitive to the change in porosity of the SVB. It is also found that relatively long waves and low porosity on SVB results in the highest wave force and short waves and high porosity on the SVB results in the lowest wave force. For most of the conditions, the wave force on SVB is less than the wave force on a single impervious vertical wall and force reduction to an extent of 20% to 80% is possible for the range of porosity and number of porous walls studied. A predictive equation to estimate the wave induced significant moment is provided with high regression coefficient. The average lever arm for assessing the wave induced moment is 0.6145 times the local water depth.