Author(s): Giovanni Di Lollo; Claudia Adduce; Moises Brito; Rui M. L. Ferreira; Ana M. Ricardo

Linked Author(s): Rui M.L. Ferreira, Claudia Adduce

Keywords: Gravity currents; PIV; Reynolds stress; TKE fluxes; Adverse pressure gradient

Abstract: The interaction between a full-depth lock-release gravity current and an emergent vertical cylinder is experimentally studied by analyzing of the changes in the velocity field. Velocity measurements are taken in a vertical plane upstream the obstacle through a 2D Particle Image Velocimetry system. The study concerns the changes in the mean velocity field, Reynolds stresses and the turbulent kinetic energy production term induced by the presence of an adverse pressure gradient by comparing the data obtained in presence of an obstacle with those obtained in the configuration without it. The obstacle doesn't induce changes in the mean flow, highlighting that the deceleration caused by the obstacle occurs in a uniform manner in the current. Instead, the spatial distribution of Reynolds stresses and consequently of the turbulent kinetic energy production is deeply affected by the obstacle. The increase in the adverse pressure gradient causes disruption of the transport from the major source of energy extraction to the backflow. Fluxes remain localized along the current front. This leads to a decay of turbulent kinetic energy within the current and its increase at the interface.

DOI: https://doi.org/10.3850/978-90-833476-1-5_iahr40wc-p0254-cd

Year: 2023