Dynamics of turbulence in a jet and the effect of swirl

Monday, May 16th – probably at MEB 10 tbc!

Samuel Davoust, ONERA, France

Jets represent an important class of turbulent flows with wide applications, from aircraft propulsion to mixing and combustion. In the first part of this experimental study, we use high-speed Particle Image Velocimetry to describe the organization and the dynamics of the largest scales of turbulence near the exit of a high Reynolds number jet. From our observations, we propose a scenario on the interaction of m=0, m=1 modes with streamwise vortices. In a second part, we focus on the changes that occur when moderate swirl is imposed, i.e. when a rotation component is added to the jet exit velocity. We detail and interpret the evolutions in the jet’s mean flow, turbulence statistics and large scale structures.