Parametric models for marine propellers

Abstract

In this work we are focusing on the presentation and comparison of two parametric models used in the generation of marine-propeller geometrical model instances. Their main function lies in their ability to automatically and quickly produce valid geometric representations of marine propellers (blades and hub) based on a small set of geometrically and physically meaningful parameters. This functionality is one of the major prerequisites when dealing with the problem of design/shape optimization of functional surfaces, such as marine propeller & wind turbine blades, that possess complex geometry and geometrically-sensitive performance. Further to this, we are also aiming at the generation of smooth, analysis-suitable instances, directly out of our parametric models, which will eliminate the time-consuming, labor-intensive and costly overhead of transforming a Computer Aided Design (CAD) model into an appropriate Computer Aided Engineering (CAE) model, commonly through an approximate mesh-model generation. The final requirement posed on these parametric models is their capacity in accurately reconstructing and representing existing propeller models. The two presented models employ a different basis for the representation of underlying free-form model surfaces, namely NURBS and T-splines, and these approaches are assessed and compared in detail with respect to the aforementioned parametric model requirements.