Recirculation system for generating opposing current in the wave flume

One of the two wave flumes at LIC has been equipped with a recirculation system designed to generate a longitudinal current flowing in the direction opposite to wave propagation, by injecting the flow from the shoreline. This configuration allows the reproduction of the hydrodynamic effect of river discharge near the coast, simulating the interaction between a freshwater inflow and incoming wave motion, as typically observed in deltas or river mouths.

The presence of an opposing current is essential for analyzing phenomena such as wave blocking, where wave–current interaction results in attenuation or partial reflection of the wave field due to the counterflow. This type of study is particularly relevant for understanding mechanisms of wave energy dissipation, coastal morphodynamics, and sediment transport processes in estuarine, deltaic, and upwelling environments.

The system is based on a closed-loop hydraulic circuit, in which water is drawn from LIC’s three-dimensional basin via a dedicated pump and conveyed into a head tank positioned upstream of the flume inlet, at the shoreline where the countercurrent is to be introduced. The head tank is equipped with an overflow system (weir) to manage excess discharge, and a motorized sluice gate that, in combination with pump flow control and the weir elevation, enables precise regulation of both the discharge entering the flume and the piezometric head at the inlet.

The pipeline from the pump to the head tank and the overflow discharge pipe are both equipped with electromagnetic flow meters. The difference between the flow rate entering the tank and the flow discharged through the overflow provides a direct measurement of the net flow introduced into the flume. The entire system is managed by a process control unit, which allows automated regulation of the pump discharge and the gate opening via motorized actuators, ensuring high precision and repeatability of test conditions.

Photographs and brochures of the system are provided.