Current measurement by use of synchronous wave probes: Method and example of laboratory experiments for progressive or partially standing waves

Abstract

In the context of studies of interactions between waves and currents, a method of calculation of the current through synchronous free surface deformation measurements at various locations is proposed and discussed in the case of either progressive or partially standing waves, and for either homogeneous or vertically sheared current. For partially standing waves, the method takes advantage of separation of incident and reflected wave method through minimization algorithms, which are still applicable in the limit case of a progressive wave. Discussions on the accuracy of the method are based on comparisons to laboratory experiments including regular and irregular waves in following or opposite current conditions. The vertically averaged current is recovered since current has a significant influence on the wave celerity. Vertically shear has less influence on the wave celerity in comparison to the averaged current in the experimental conditions considered, and is hardly directly recovered because of the noise inherent to the measurements. However the shear can be estimated through the calculated vertically averaged current which depends on frequency in the presence of shear. The present study concerns the unidirectional case, including regular or irregular waves.