3D Gravity Currents on Smooth and Rough Bed

In this paper, a numerical and experimental study on gravity currents is presented. Such currents are generated in a rectangular tank, whose bottom is characterized by different roughness conditions, by the contact of fluid bodies with different densities. By using an image acquisition system, it is possible to record the time evolution of the dense wave front, while two laser sensors give the instantaneous thickness of the dense layer in two different points. Numerical modeling is based on the shallow water and immiscibility hypothesis. The shallow water hypothesis makes sense due to the small value of the ratio between vertical and horizontal characteristic lengths of gravity current. The immiscibility hypothesis makes sense as the Richardson number of the considered runs is sufficiently high. The comparison between numerical and experimental results is encouraging and shows that shallow water modeling is an useful predictive tool from the technical point of view. -