Seminal work of Stokes, based on linear wave theory, suggest that there is a net forward drift in the fluid beneath a propagating surface wave. However, a recent work supported by field measurements suggest that in many cases, particularly in waves propagating over a shear flow, either a net forward or backward Eulerian flow may develop according to the local average water depth. In this work we further investigate what has been observed in the field by means of laboratory experiments in a wave flume, where monochromatic short waves and bichromatic (short + long) waves are run. Fluid particles are tracked and their velocity evaluated through Particle Tracking Velocimetry (PTV) and processed to extract vertical profiles of longitudinal velocity. Fluid trajectories are to be compared with theoretical predictions.
