Numerical Simulation On Ventilated Supercavity Based On Two Fluid Model And Acceleration Influence Analysis

Supercavitation technology is a new theory and approach which realizes high speed navigation of water vehicles.The main principle of its reduction drag is using a layer gas on body wall make the moving body isolated from water to avoid considerable viscous forces.The theoretical studies of cavitation primarily utilize the potential flow theory.Studies dealing with cavitation modeling through the computation of the N–S equations have emerged in the last decade.The current cavitation models can reasonably model natural cavity, but the simulation of ventilated supercavity is used mostly homogeneous multiphase model, which results in the big difference between simulated and experimental results. In this paper based on two fluid model and the dynamic grid technologies, the cavitator and supercavity vehicles are numerically simulated with consideration of the gas-water interaction and the gravity effect. The main works are as follows:( 1 ) The influence of different turbulence models to gas ventilation coefficient has been investigated. The development process of the ventilated supercavity under the different ventilation rates is shown through numerical simulation. The grid has been verified. The cavity shape and resistance differences of the 3D vehicles are compared with the combin walls and without the combin walls.(2)Based on two fluid model and SST turbulence model, the scale effect on the ventilated supercavity are investigated in the bounded flow field and unbounded flow field with consideration of the gas-water interaction and the gravity effect. The rules of the cavity shape and resistance are obtained. In the unbounded flow field ventilation rate and cavity shape formula is given.(3)By changing the model of feature length to change the size of the Froude number, we observe the effect of the Froude numebe changes on the the extent of the upper cavity drift from another angle.(4)Using dynamic grid technology, cavitator accelerated motion, can better simulated the acceleration on the effect of the supercavity in the actual flow. Different acceleration on the effect of the cavity shape and resistance are compared in the the natural cavitation and the ventilated cavitation.