This paper investigates the impact of small-scale unsteadiness on adjoint-based output sensitivity analysis. In particular, when iterative methods for nonlinear flows fail to converge to a steady state, it is demonstrated that the resulting sensitivity analysis can be highly inaccurate, evenwhen the unsteadiness in the outputs is small. The specific example considered is the viscous subsonic fl...

A reduced-order model (ROM) is developed for aeroelastic analysis using the CFL3D version 6.0 computational uid dynamics (CFD) code, recently developed at the NASA Langley Research Center. This latest version of the ow solver includes a deforming mesh capability, a modal structural de nition for nonlinear aeroelastic analyses, and a parallelization capability that provides a signi cant increase...

This research proposes an algorithm for the simulation of time-periodic unsteady problems via the solution unsteady Euler and Navier-Stokes equations. This algorithm which is called Time Spectral method uses a Fourier representation in time and hence solve for the periodic state directly without resolving transients (which consume most of the resources in a time-accurate scheme). Mathematical t...

Aquasi-three-dimensional multigrid Navier–Stokes solver on singleandmultiple-passage domains is presented for solving unsteady  ows around oscillating turbine and compressor blades. The conventional direct store method is used for applying the phase-shifted periodic boundary condition over a single blade passage. A parallel version of the solver using the message passing interface standard is ...