Turbulence and Void Distribution in Horizontal Counter-Current Stratified Flow
Thomas D. Stäbler, Leonhard Meyer, Thomas Schulenberg and Eckart Laurien
The aim of the present investigations is to provide local experimental data for horizontal stratified flows under counter-current conditions. Measurements of the velocity and turbulence distribution up to the free surface were conducted with the laser-optical method of Fluorescent Particle Image Velocimetry (FPIV). Void fractions were measured with a resistivity probe. Different flow regimes, namely supercritical and subcritical flow and partially reversed flow are presented. The measured local velocity, turbulence and void distributions are presented and discussed. By correlating the measured void fraction with the turbulent kinetic energy calculated from the measured velocity fluctuations a theoretical closure equation is derived. This equation is validated with the experimental data and can now be used for numerical modeling.
Keywords: Counter-current, stratified, two-phase, free surface, turbulence, void, fluorescent particle image velocimetry (FPIV), resistivity probe.