Flow Modelling for partially Cavitating Two-dimensional Hydrofoils

The present work addresses te computational analysis of partial sheet hydrofoil cavitation in two dimensions. Particular attention is given to the method of simulating the flow at the end of the cavity. A fixed-length partially cavitating panel method is used to predict the height of the re-entrant jet, using the values of the cavitation number and the drag coefficient. The jet surface is subsequently constructed and inclued in an updated cavity shape. At the same time, a source singularity is introduced in the fluid domain to account for the mass flux through the part of the domain boundary represented by the re-entrant jet surface. Further iterations are performed for fixed cavitation number on the cavity with a re-entrant jet cavity termination model. This model is seen to produce good results and displays quick convergence. A validation is accomplished by conducting a parametric analysis of the model and comparing the present calculations with numerical results. The flow around the partially cavitating hydrofoil with a re-entrant jet has also been treated with a viscous/inviscid interactive method. The viscous flow model is based on boundary layer theory applied on the compound foil, consisting of the union of the cavity and the hydrofoil surface. The change in the flow direction in the cavity closure region is seen to have a slightly adverse effect on the viscous pressure distribution. Otherwise, it is seen that the viscous re-entrant jet solution compares favourably with experimental results.