Design-by-Morphing: A Shape Design Methodology for Fluid Machinery

Even with years of experience, the intuition of skilled engineers often falls short when designing around fluid flows. The non-intuitive behavior of fluids can mean the optimal geometry of fluid machinery is surprising or even extreme (consider, for instance, the bulbous bow of a ship). Conventional design techniques, such as parametric or control point methods, optimize small segments of geometry and do not easily allow for the discovery of such out-of-the-box designs. These techniques are also hampered by designer bias and a high number of design parameters. Here we present Design-by-Morphing (DbM), a novel methodology for shape design, that overcomes the limitations of traditional strategies. DbM works by weighting homeomorphic (i.e., topologically equivalent) shapes with positive weights (exploration) and negative weights (extrapolation) and combining them together to create a continuous search space that can produce radical geometries from a few design parameters and without designer bias. We present our application of DbM for the shape optimization of airfoils, draft-tubes for hydrokinetic turbines, and vertical-axis wind turbines. In all cases, we show significantly improved and radical designs.