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Accueil > Actualités > Événements > Événements 2018

JEts interacting with VEgetation in Rotating Basin (JEVERB)

Contaminants, nutrients and sediment particles flow into our inland and coastal water bodies often forming turbulent jets. Some examples are outflows from rivers, sources and discharges entering the ocean through natural obstructions. Mixing processes are rather well understood for unobstructed jets, and they are mainly controlled by the initial jet characteristics, the boundary conditions and the hydrodynamic features of the ambient current. Jets obstructed by vegetation have been investigated only recently and have shown to play an important role. For example, while in the absence of vegetation the entrainment in the jet is a dominant process, the vegetation canopy has been found to induce detrainment. In the case of a uniform flow, previous research has demontrated that vegetation canopy strongly perturbs advection and dispersion depending on its density and geometry.

In realistic contexts, the effect of rotation on the turbulence induced by an obstructed pattern is felt indirectly through the modification of the mean flow, and so the subsequent transport and spreading of turbulent kinetic energy and scalars (tracers). Furtherly, rotation may induce the development of Ekman boundary layers, which effectively increases bottom friction and could alter the turbulence characteristics within the jet.

Laboratory studies investigating the effect of the earth’s rotation of a jet propagating through vegetation do not exist to date and are the goal of the present experiments. Variation parameters are the vegetation disposition and the different background rotation speeds, for a given output flow rate of the jet. Velocity fields are captured at different horizontal 2D cross sections using a PIV measurement technique, ADV point measurements and dye visualizations and will enable to obtain detailed information about the mean and turbulent flow characteristics.

Project Leader :

Francesca De Serio - Polytechnic University of Bari, Italy

Member :

European project Hydralab+