Turbulent jet through porous obstructions under Coriolis effect: an experimental investigation

Francesca De Serio,Thomas Valran,Joel Sommeria,Dan Liberzon,Giuseppe R Pisaturo,Samuel Viboud,Donatella Termini,Roni H Goldshmid,Michele Mossa,Maurizio Righetti,M Eletta Negretti

doi:10.1007/s00348-021-03297-2

Abstract

The present study has the main purpose to experimentally investigate a turbulent momentum jet issued in a basin affected by rotation and in presence of porous obstructions. The experiments were carried out at the Coriolis Platform at LEGI Grenoble (FR). A large and unique set of velocity data was obtained by means of a Particle Image Velocimetry measurement technique while varying the rotation rate of the tank and the density of the canopy. The main differences in jet behavior in various flow configurations were assessed in terms of mean flow, turbulent kinetic energy and jet spreading. The jet trajectory was also detected. The results prove that obstructions with increasing density and increased rotation rates induce a more rapid abatement of both jet velocity and turbulent kinetic energy. The jet trajectories can be scaled by a characteristic length, which is found to be a function of the jet initial momentum, the rotation rate, and the drag exerted by the obstacles. An empirical expression for the latter is also proposed and validated.Graphic abstract

Highlights

Rivers and wastewater discharge into lakes and coastal waters often form turbulent jets
Some researchers (e.g. Ben Meftah et al 2015) define the jet trajectory as the locus of maximum jet velocity, while others (New et al 2006) as the streamline starting from the center of the jet
For all the experiments investigated (Table 1), some selected transversal profiles are plotted in the left panels of Fig. 4, while the overall velocity fields together with the jet trajectory are plotted in the right panels of Fig. 4

Summary

Introduction

Rivers and wastewater discharge into lakes and coastal waters often form turbulent jets. Long-shore and cross-shore coastal currents can be intended as jet-like flows in some cases when constrained by local topography or manmade structures. These types of environmental flows all have a profound effect on aquatic ecosystems due to the transport of turbulence, tracers, and sediment particles. The surrounding environment affects their mixing and dispersion processes. Our ability to predict their behavior strongly depends on our capacity to describe how jets interact with the real environment they discharge into. 1 3 Vol.:(0123456789) 218 Page 2 of 15

Methods

Results

Conclusion