Experimental investigation of a stratified buoyant wake

Abstract

An existing water channel facility at Texas A&M University is used to experimentally study a stratified, buoyant wake. A cylindrical obstruction placed at the centerline of a developing Rayleigh-Taylor mixing layer serves to disturb the equilibrium of the Rayleigh-Taylor mixing layer. The development of the near wake in the presence of unstable stratification is examined, in addition to the recovery of the buoyancy driven mixing layer. Planar laser induced fluorescence (PLIF) is used to visualize the mixing layer / wake interactions, and qualitative observations of the behavior have been made. Also, quantitative measurements of velocity fluctuations and density fluctuations in the near wake have been obtained using particle image velocimetry (PIV) and a high resolution thermocouple system. These experimental measurements were used to investigate how the wake and buoyancy driven mixing layer interact. Finally, a mathematical model has been used to describe the decay of vertical velocity fluctuations in the near wake due to the effects of buoyancy.