2D Experimental Study of Waves and Current Contribution to the Nearbed Velocities and Shear Stresses Field

Most of what is known about flow under waves and currents has been deduced from numerical models and not always validated. Absence of accurate experimental and field data, including measurements within the boundary layer or in its vicinity, makes the observation and study of the interaction between steady and oscillatory flow together with model validation difficult. A series of 2D experiments has been done in a laboratory flume. Velocity profiles obtained under different conditions have been analyzed. In addition, a simple 1DV model for turbulent boundary layer simulation has been used. Computed near bed velocities and roughness length are compared with experimental results. By means of three methods based on experimental and numerical results, variations of friction forces as a result of the interaction between the oscillatory and the steady components are evaluated.