SPECTRAL ANALYSIS OF TURBULENT BOTTOM SHEAR STRESS UNDER IRREGULAR WAVES

A method to compute turbulent bottom shear stress from free stream velocity variation under irregular waves has been proposed for plane bed condition. The correlation has been assessed through spectral analysis of free stream velocity and bottom shear stress obtained from generated irregular waves and from k-ε model result respectively. A significant improvement in the prediction has been achieved compared to that proposed by the authors earlier. Turbulent friction factor and phase difference obtained through spectral analysis corresponds quite well to those from experimental data for sinusoidal waves and with corresponding available smooth turbulent friction factor descriptions. Proposed method presents a high degree of accuracy and is very convenient to use from the viewpoint of practical application.