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A new numerical treatment has been developed for the prediction of the flowfield resulting from an attached cavitation region. The cavitation model has been implemented in a viscous calculation which is an improvement over previous inviscid results. The model requires no apriori knowledge of the wall detachment point or bubble length and comparisons with experimental data indicate good predictions of these quantities for a variety of different body shapes and cavitation numbers. Furthermore, wall pressure distributions are also predicted quite accurately using this method. While the treatment has been applied to an axisymmetric calculation, the approach should be applicable to two-dimensional flows.

A nonlinear numerical model has been developed to assess nonequilibrium effects in cavitating flows. The numerical implementation involves a two-phase treatment with the use of a pseudo-density which varies between the liquid and gas/vapor extremes. A new constitutive equation for the pseudo-density is derived based on the bubble response described by a modified form of the Rayleigh-Plesset equation. Use of this constitutive equation in a numerical procedure permits the assessment of nonequilibrium effects. This scheme provides a quantitative description of scaling effects in cavitated flows. With minimal modifications, the model can also be used for bubbly two-phase flows.

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Complexation of amines with borane converts them to hypergols or decreases their ignition delays (IDs) multifold (with white fuming nitric acid as the oxidant). With consistently low IDs, amine-boranes represent a class of compounds that can be promising alternatives to toxic hydrazine and its derivatives as propellants. A structure-hypergolicity relationship study reveals the necessary features for the low ID.