A Fast Adaptive Resolution Method For Efficient Free Wake Calculations

The Fast Adaptive Subvortex Technique is a new free wake method that provides the accuracy of curved element methods with the computational efficiency expected of simpler but less accurate elements. The wake is modeled as a collection of vortex filaments, which are discretized into simple vortex particle elements. For the infrequent near-field calculations, the element resolution is locally increased for accuracy, while the more frequent far-field calculations are done with a lower element resolution for efficiency. Consequently, the minimum number of elements is used for a given level of accuracy. The code was structured to vectorize efficiently for additional performance enhancements. Comparisons to curved element methods using prescribed wakes and rotor free wake simulations show that the method can yield over an order of magnitude gain in efficiency while providing comparable accuracy.