Application of a High-Order Accurate Implicit Method to Rotor Aerodynamics

The objective of this proposal is to apply a new high-order accurate in space computational approach in the OVERFLOW code in order to resolve the essential features of helicopter flowfields more efficiently. The potential of the proposed method to improve resolution of tip vortices and rotor wakes at reduced computational cost will be demonstrated. The innovative aspect of the method is that the high¿order of accuracy of the implicit operators is obtained at very little additional computing cost by applying compact space discretization. The proposed method yields time¿accurate numerical solutions of the inherently unsteady helicopter rotor flowfields more efficiently than current methods. Tests for time integration of wave¿type andinviscid flow problems showed that the new, implicit, high¿order accurate in space method is superior in terms of achieved accuracy versus computational cost when compared with classical second¿order accurate in space implicit methods. The ADI high¿order method will be extended to curvilinear meshes and viscous flows to obtain solutions for realistic problems. In Phase I, the method will be implemented in the OVERFLOW code and the vortex blade interaction problem will be solved and in Phase II solutions of helicopter flowfields will be obtained.