Wake-Capturing Methods for General and Heavy-Lift Rotorcraft Flow Analysis

There is a very important aspect of rotorcraft aerodynamics that cannot now be computed, within engineering time constraints, with engineering methods now in use. This is the rotor wake, as well as the many aspects of its interaction with the rest of the rotorcraft. Unlike conventional aircraft, there are a very large number of flight regimes to be treated and during a rotorcraft design phase, a very large number of computations must be done, so that each computation must be done in a short time. The two main approaches currently used in aerodynamic computations: Conventional CFD and panel or vortex lattice methods are far away from being able to solve the general wake problem. However, there are basic ideas implicit in both that can lead to a fully satisfactory, efficient treatment of all important effects of the wake, in all fight regimes. We describe the features of each method that make it inadequate for the general problem, and the basic idea in each that can be used to make a new approach that will be effective. This approach is known as ¡°Vorticity Confinement¡±. We then describe the sequence of tasks that will achieve these objectives.