A Non-Viscous Investigation of Mesh Refinement and Sweep Angle Effects on Combat Fighters

Abstract

© 2024, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved.This manuscript discusses the impacts of two factors on the results of a non-viscous CFD simulation of a combat aircraft: mesh refinement and the leading-edge sweep angle. Unlike viscous simulations, the non-viscous simulation of a delta wing with a rounded leading edge has a unique characteristic where mesh refinement consistently alters the flow topology, making mesh independence analysis ambiguous. To investigate this phenomenon further, the Generic Future Fighter, an aircraft initially devised by Linköping University and further studied in conjunction with Instituto Tecnológico de Aeronáutica, was used to validate this issue through aerodynamic coefficients obtained from wind tunnel tests from another work. Subsequently, using the mesh that yielded the most accurate results, the leading-edge sweep angle was varied while keeping the rest of the aircraft and other wing geometric parameters constant. The results of the first phase confirmed that mesh refinement progressively delays the separation of the leading-edge vortex. The results of the second phase were inconclusive, highlighting several points that require further investigation. The manuscript also presents a discussion on the highly nonlinear interaction between the canard vortex and the wing vortex, as well as the effect of the mesh on these interactions, an aspect lacking in recent studies which typically consider only a single lifting surface.