A Dynamical System Model for the Co-Flowing Buoyant Jet

The buoyant co-flowing jet breaks self-similarity in two ways: the transition from strong to weak jet, and the jet regime versus the plume regime. Previous work has shown that, for the self-similar jet, using an integral method the turbulence model equations can be reduced to a dynamical system with a single attracting fixed point that is the self-similar state. Here, the same technique is used to analyze the buoyant jet experiments of Charonko & Prestridge (JFM 2017). In this more complex case there appears to be a low-order attracting manifold which dominates the jet behavior, analogous to the fixed point in the self-similar case. Experimental data and results of RANS simulations are used to investigate this structure in both the model and the real world.