Bio-Mimetic Concepts for Next-Generation Turbomachinery

Harbor Seal whisker samples were obtained from the San Diego Zoo for analysis using both microscopes and computed tomography (CT) to obtain an accurate 3D geometry. The geometry was then parameterized in a CAD model based on seven variables which accurately represent the whisker geometry. The new HPC hardware consists of four Intel Xeon 7120A Phi cards which provides access to 244 cores (4.8 teraflops) of computing resources in one office environment workstation. A novel CFD code (XFlow) is utilized which allows for very fast and accurate large eddy simulations (LES), based on the Lattice-Boltzmann method. The use of modern computing equipment coupled with innovative CFD tools allows for rapid design evaluations on the order of hundreds or even thousands of computed results. In order to automate the search for an optimal geometry, a software integration and optimization tool is used to iterate though many designs to find a set of optimal solutions. The first application of interest demonstrates that this synthetic evolution architecture does find the Harbor Seal whisker geometry to be an optimal solution based on the two objectives of minimizing the RMS vortex induced vibrations (VIV) and minimizing induced drag. The parameterized geometry initially begins as a perfect cylinder, which exhibits very poor RMS VIV and drag characteristics. After several hundred iterations driven by a global optimization routine, the optimized geometry converged to a shape very similar to the Harbor Seal whisker. This automated architecture will be implemented to drive the optimization of bio-inspired airfoils towards increased performance characteristics and lower noise signatures. The disrupted vortex shedding characteristics enhances trailing edge wake dissipation as well as shifting wake frequencies higher past the audible range. More »