Flow development of buoyant round jets in cross-flow*

The physics of wind-bent plumes has been studied for many applications, including volcanic ash transport models used to predict hazards. Simple laboratory experiments of air jets in crossflow provide a deeper understanding of the interaction and mixing with cross-flow. Because volcanos are more complicated than these experiments, jets of air, helium, and argon (Re $\approx 10^5$) are injected orthogonally into a closed-loop wind tunnel with several cross-flow velocities to compare varying densities. Mean flow statistics are collected using particle image velocimetry (PIV) to characterize the interactions between the cross-flow and jet. These are used to identify the leading edge and lee-side shear layer where the inertial and Reynolds stress terms of the momentum and energy equation are evaluated. By varying the density of the jet and changing the inflow conditions, relationships for the rate of entrainment through the bending region can be evaluated for negative, neutral and positively buoyant plumes.