ACCURACY AND COUPLING ISSUES OF AEROELASTIC NAVIER-STOKES SOLUTIONS ON DEFORMING MESHES

An implicit time-accurate approach to aeroelastic simulation was devel oped with particular attention paid to the issues of time accuracy, st ructural coupling, grid-deformation strategy, and geometric conservati on. A Beam-Warming, approximate-factored algorithm, modified to includ e Newton-like subiterations was coupled with a structural model, also in subiteration form. With a sufficient number of subiterations, this approach becomes a fully implicit, first- or second-order-accurate aer oelastic solver. The solver was used to compute time-accurate solution s of an elastically mounted cylinder. The fully implicit coupling allo wed the overall scheme to become second-order accurate in time, signif icantly reducing the workload for a given accuracy. A new algebraic gr id deformation strategy was developed that preserves grid orthogonalit y near the surface under large deformations. Finally, the oscillatory behavior of an elastically mounted cylinder was reproduced accurately by the present approach, and results compared favorably to previous ex periments and simulations.