Indicial aerodynamics in compressible flow-direct computational fluid dynamic calculations

An innovative indicial/gust response measurement technique for airfoils provides naturally decoupled loading parameters while overcoming the problems associated with step changes at the boundaries. An implementation of the technique into a Euler/Navier-Stokes solver enables direct calculation of the indicial responses as a function of step changes in angle of attack. The use of computational fluid dynamics gives a grid-velocity framework that is as accurate as known analytical results for linear flowfields. However, the agreement turns worse for increasingly nonlinear flowfields.