Unsteady dynamic analysis for the cavitating hydrofoils based on OpenFOAM

Recently, cavitation has attracted great attention not only due to its negative effect on the performance of fluid machinery, but also owing to its vigorous prospect in drag reduction for underwater vehicles. However, strong instability and obvious nonlinearity exist for cavitating flow, making it hard to predict it precisely. In this paper, a cavitating solver coupled with the Bubble-Droplet cavitation model has been established based on the OpenFOAM platform. Simulation has been carried out for the cavitating hydrofoil of Clark-Y. Transient evolutions of the flow parameters including the void fraction, velocity, and pressure have been obtained, giving detail insights on the unstable shedding dynamics for the cavitating hydrofoil. Evaluation of the Bubble-Droplet cavitation model has been implemented by varying the threshold value in the model. The transient cavity shape, shedding frequency, and time-dependent curves for the hydrodynamic coefficient have been carefully compared, indicating that this threshold value has obvious effect on the cavity profile during the shedding process. By comparing with the experimental data, the predicted lifts are slightly under-predicted while the drags are over-predicted, but basically the numerical results agree with the experiment well.