F-16XL simulations at flight conditions using hybrid near-body/offbody computational fluid dynamics

Abstract

The F-16XL flight vehicle has been used extensively to study the aerodynamics of medium-To high-Angle-of-Attack flight. Flight-Test data, including surface pressures, are available for a wide range of flight conditions, allowing direct comparison between computational fluid dynamics and full-scale flight data. The most recent comprehensive study, made possible by NASA, was conducted by NATO Task Group AVT-113 and had participants from many different countries. One of the conclusions of the study was that unsteady flow simulations with high-resolution turbulence treatment was necessary to compare well with the high-Angle-of-Attack flight-Test data. The current work applies the high performance computing CREATE™-Air Vehicles Kestrel fixed-wing simulation tool to the F-16XL configuration at high-Angle-of-Attack flight conditions. Kestrel couples a near-body spatially second-order solver with an offbody, spatially third- or fifth-order solver to achieve a very high-resolution computation of the aerodynamic features of the flowfield. Adaptive mesh refinement is also performed in the offbody domain as the solution progresses to maintain the vortical structures away from the body. The resulting simulation data are compared to flight-Test data, and they are found to be in very good agreement for this flight condition.