Towards Large Eddy Simulation of Cavitation in Hydraulic Valves

The thesis of this paper is that cavitation in hydraulic spool valves involves large-scale vortical structures in an unsteady submerged jet. Current computational fluid dynamics approaches do not accurately predict these unsteady vortices, nor do they properly account for bubble-dynamics/flow-structure interactions. The large eddy simulation turbulence model was considered to overcome these deficiencies. First, a commercial code was applied to study cavitation in a model spool valve, addressing the effects of including a cavitation model and the large eddy simulation turbulence model. Second, a research code was developed to study the effect of cavitation inception on vortex dynamics in a submerged planar jet. A previously developed cavitation model, which accounts for interactions between large-scale vortical structures and cavitation bubbles, was employed. Results were obtained which demonstrate that even low levels of cavitation have significant effects on the jet vortex dynamics, including vortex intensification and splitting. An analysis of the vorticity transport equation reveals the underlying mechanisms behind these effects.