The objective of this project is to develop a unified computer code that can be used to design and analyze a wide variety of propulsor types, including conventional and highly skewed open propellers; ducted propellers; multicomponent propulsors – with and without ducts; integrated propulsors; and waterjets.

To achieve this degree of versatility, two major changes to previous design-analysis methodologies were introduced: (1) Blade geometry was defined by B-spline surfaces rather than by traditional measures, such as pitch, rake and skew. In this way, propulsors designed to operate with large flow conicity (such as integrated propulsors or mixed-flow waterjets) can be accommodated without the introduction of special features. (2) The flow field has been represented by a consistent decomposition into its axisymmetric and nonaxisymmetric parts. The former is computed by either an axisymmetric Reynolds-averaged Navier-Stokes code or by a coupled Euler/boundary-layer code. The nonaxisymmetric part is computed by a vortex-lattice lifting-surface procedure. The two flow fields are coupled by means of body forces. With this procedure, the vortical interaction between the propulsors and the inflow (the so-called effective-wake problem), and the axisymmetric interaction between blade rows are accounted for. This procedure has been employed recently to design a mixedflow waterjet pump; model tests carried out in the MIT Marine Hydrodynamics Water Tunnel have confirmed that the predicted operating point was achieved, and the cavitation characteristics of the new design were superior to those of an existing baseline pump.