Evaluation of High- and Mid-Fidelity Computational Fluid Dynamics for Complex Ship Airwake Analysis with New Experimental Data

Abstract

Safe flight with maneuvers of rotorcraft systems in the near vicinity of Naval ships poses a number of challenges due to the complex, unsteady wake shedding from the ship surface. To prepare pilots to operate in these conditions, it is desired to ensure accurate ship airwake simulation capabilities that provide an understanding of the flow field and are sufficiently cost-effective so that they can be applied in flight simulators to enhance pilot training and safety. While the simple frigate shape (SFS2) geometry has been extensively studied, assessments of the flow environment with respect to practical usage in flight simulations have experienced fewer analyses. A high-fidelity, conventional unsteady unstructured Reynolds-Averaged Navier-Stokes CFD solver (FUN3D) and novel time-resolved particle image velocimetry measurements are evaluated with Lattice-Boltzmann Method (LBM) simulations to understand LBM's potential for real-time flight simulations. LBM predictions are overall relatively comparable to FUN3D and PIV, albeit with some loss in magnitude and detail, but at computational time savings of several orders of magnitude to unstructured CFD. Ship orientations with yaw experiencing winds have more differences between LBM and FUN3D than non-yawed orientations.