Numerical study on ventilated cavitation influenced by injection of drag-reducing solution

The influence of injection of drag-reducing solution on ventilated partial cavitation and supercavitation for an axisymmetric underwater vehicle is analyzed by numerical simulation. Turbulence, cavitation and multiphase models are SST κ -ω Schnerr-Sauer and Mixture models, respectively. The Cross viscosity equation is adopted to represent the fluid property of aqueous solution of drag-reducing additives. First of all, for non-cavitating conditions, the pressure distribution is obtained to determine the positions of injecting drag-reducing solution and ventilation. Then natural cavitation at different cavitation numbers is investigated for acquiring inception cavitation number. Finally, numerical simulations are conducted on the ventilated cavitating flows with and without the injection of drag-reducing solution at the cavitation number slightly smaller than the inception cavitation number (partial cavitation) and much smaller than the inception cavitation number (supercavitation). It is shown that for partial cavitation, the shape of cavity with the injection of drag-reducing solution is larger and the resistance of underwater vehicle decreases in comparison with the case without the injection of drag-reducing solution. However, for supercavitation, just viscous drag force obviously decreases, while cavity shape does not change.