Quasi-Steady Vortex Tracking in Rotorcraft CFD on the Cray X1

High-fidelity, far-field and economical blade vortex capturing, tracking and subsequent interaction is one of the most important aerodynamics problems in rotorcraft, particularly for heavy lift. Its solution is also one of the most difficult to obtain. This paper documents the use of multiple helical vortex tracking grids and development of an automated tracking technique to achieve this objective. This technique is tested on the interactional aerodynamics of a generic quad tilt rotor (QTR). This paper also highlights the special issues that arise in the parallelization of an in-house overset CFD code using the one-sided communication model of Co-Array Fortran (CAF) implemented on the Cray XIE