Numerical approaches for hydrodynamic cavitating flows
Abstract
Numerical approaches for simulating hydrodynamic cavitating flows have been investigated. First, a new numerical treatment has been developed for the prediction of the flowfield resulting from an attached cavitation region. While the treatment has been applied to an axisymmetric calculation, the approach should also be applicable to two-dimensional flows. The cavitation model has been implemented in a viscous calculation which is an improvement over previous inviscid results. A two-phase model has been established to address more general cavitating flows: such as unsteady, vortex cavitation. The two-phase treatment is accomplished through the addition of a pseudo-density which varies in magnitude between the vapor and liquid densities. A new treatment has been developed to provide the additional relationship required as a result of the inclusion of this new fluid variable. The model has been compared to experimental data for external flows over axisymmetric headforms and calculations of an internal flow in a sharp-edged orifice passage are also discussed. Based on the two-phase approach, a numerical model to assess non-equilibrium effects in either cavitating or bubbly flows is developed. A new constitutive equation for the pseudo-density is derived based on the bubble response described by a modified form of Rayleigh's equation. Use of this constitutive equation in a numerical procedure permits the assessment of non-equilibrium effects. Finite thickness shock waves are resolved in bubbly flows through Delaval nozzles, and scaling effects are described quantitatively for cavitating flows.
Degree
Ph.D.
Advisors
Heister, Purdue University.
Subject Area
Mechanical engineering|Aerospace materials
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