Financial support : Institut Carnot "Energies du futur"
This study focuses on numerical simulation of liquid jets (plane or axial) sheared by a high-speed stream, for a better understanding of the flapping instability occurring for both geometries. This numerical study is performed at moderate density and velocity ratio between phases. The flapping dynamics of a plane liquid sheet is a consequence of the pressure difference between the two sides of the sheet. A study of the flapping control is performed, as well as a sensitivity study to the high-speed stream boundary layer thickness, and a relevant Strouhal number is proposed. The study focusing on coaxial jets raises a different flapping mechanism: due to high-speed stream shear, interfacial waves are observed near the injection and are likely to get connected, inducing a sinuous organization to the whole jet. The passive and active control of this flapping is studied, as well as the influence of some injection parameter. The momentum-flux ratio (M) isn’t characteristic for the flapping dynamics. Some air-water simulations of an experimental flow studied at LEGI are finally performed. A forcing applied to the liquid inlet is necessary to get interfacial instabilities. Pressure oscillations are evidenced in the gaseous flow inside the nozzle, as well as Görtler vortices.
Publications
Peer-reviewed Publications
2018
2015
Conference Proceedings
2014
Ph.D. Theses
2014
