Influence of surface waves on the propagation of a gravity current

In this work, experimental and numerical results relative to gravity currents are presented. Gravity currents are realized by means of lock exchange release experiments in the presence of surface waves. Experiments have been carried out in a laboratory flume equipped with a wavemaker at one end and an absorbing beach at the other end. The region comprised between the wavemaker and the lock has been filled with salt water, while the remaining part of the channel has been filled with fresh water. At time t=0 the lock was lifted and at the same time the wavemaker was turned on, generating a sinusoidal surface wave. The evolution of the experiment was filmed and the shape and the front position of the gravity current were gathered. Numerical results have been obtained by means of a two-layer shallow water Lattice Boltzmann model and compared to experimental results. The agreement has been found fairly good, both confirming that the Lattice Boltzmann Method is a versatile tool in simulating two-layer shallow water flows and highlighting the dynamics of the flow as a whole