Wave transmission and reflection characteristics of a partially immersed rigid vertical barrier

Abstract

The wave transmission and reflection by a partially immersed rigid vertical barrier was studied in detail in deep water conditions by measuring the transmitted and reflected wave histories. The experimental investigations were carried out for a wide range of wave steepness, at different depths of immersion of the barrier in a wave flume 0.3 m wide, 10 m long and in a constant water depth of 0.8 m at Ocean Engineering Centre, Indian Institute of Technology, Madras, India. The power transmission theory proposed by Wiegel [(1960), Transmission of waves past a rigid vertical barrier. J. WatWay Harbour Div., ASCE WW1, 1–12] was used for validation of the measurements. This theory is found to predict satisfactorily the wave transmission for wave steepness up to 0.05, especially when the depth of immersion of the plate is more than about 20% of the water depth. The measured coefficient of reflection is found to be decreasing with increase in wave steepness. The maximum value of coefficient of transmission is found to be only about 0.15 for horizontal water particle excursion at the bottom tip of the barrier of up to twice the thickness of the barrier. The coefficient of energy loss is found to increase with the increase in wave steepness. This energy dissipation is found to be more predominant during the process of reflection than transmission.