On the limiting parameters of artificial cavitation applied to reduce drag

Artificial cavitation, or ventilation, is produced by releasing gas into liquid flow. One objective of creating such a multiphase flow is to reduce frictional and sometimes wave resistance of a marine vehicle completely or partially immersed in the water. In this paper, flows around surface ships moving along the water-air boundary are considered. It is favorable to achieve a negative cavitation number in the developed cavitating flow under the vessel's bottom in order to generate additional lift. Cavities formed in the flow have limiting parameters that are affected by propulsive and lifting devices. Methods for calculating these influences and results of a parametric study are reported

Complex numerical modeling of dynamics and crashes of wing-in-ground vehicles

The Wing-In-Ground craft (WIG), a vehicle flying in the ground effect, is a promising transportation means of the near future. This paper describes mathematical modeling of WIG motion in all regimes, such as planing, take-off, transition to flight, and flight itself. The model, which includes nonlinear hydroaerodynamics, serves as a base for simulation of motion. The theory developed here enhances the process of designing WIG vehicles; its advantages and disadvantages are discussed. The results of numerical modeling are compared with experimental data obtained for planing and flight regimes of motion. The model is applied for studying emergency problems in WIG operation

Stochastic six-vertex models, Hall-Littlewood positivity and tt-deformed Schensted insertions

We prove a positivity theorem for a certain family of operators defined in terms of the stochastic six-vertex model. We explore connections of this result with other vertex models and $t$-deformed Schensted insertions

Theory of Coulomb Blockade in Semiconductor Devices

Contains a description of one research project, a report on one research project and a list of publications.Joint Services Electronics Program Grant DAAH04-95-1-003

Hydrodynamics of single-deadrise hulls and their catamaran configurations

AbstractAsymmetric planing hulls are often used on high-speed catamarans. In this study, a linearized potential-flow method is applied for modeling steady hydrodynamics of single asymmetric hulls and their catamaran setups. Numerical results are validated with available experimental data and empirical correlations. Parametric calculation results are presented for the lift coefficient and the center of pressure for variable hull geometry, spacings, and speed regimes. The lift coefficient is found to increase at smaller hull spacings and decrease at higher Froude numbers and higher deadrise angles