Computational Study of the Abrupt-Wing-Stall Characteristics of F/A-18E and F-16C

Steady-state computational-fluid-dynamic (CFD) simulations are used to gain an understanding of the physics behind the abrupt-wing-stall (AWS) phenomenon and to arrive at static figures of merit (FOMs). Navier‐Stokes solutions are obtained using the NASA Langley Research Center developed TetrUSS simulation suite, which is based on tetrahedral, unstructured grids. The physics of the AWS phenomenon is understood by comparing CFD simulation results on two aircraft; a preproduction F/A-18E configuration, which exhibits AWS phenomenon under certain geometric and flow conditions, and an F-16C aircraft configuration that does not. The computational results are used to understand the possible causes of AWS by comparing the detailed flowfields between the two configurations under a variety of flow conditions. Based on this approach, a number of static figures of merit are developed to predict AWS. The potential FOMs include the break in the lift and wing-root bending moment vs angle of attack α and the rate of change of sectional lift with respect to α .A companion paper describes a similar study for the AV-8B Harrier and F/A-18C.