Numerical Simulation of Manoeuvring Aircraft by Aerodynamic and Flight-Mechanic Coupling

Abstract

This paper presents results of simulations performed within the scope of the DLR-Project AeroSUM-
\n“Aerodynamic Simulation of Unsteady Manoeuvres”. The objective of the AeroSUM-Project is to
\ndevelop a numerical tool to simulate the unsteady aerodynamics of a free flying aircraft, by use of
\ncoupled aerodynamic and flight-mechanic computations. To achieve this objective, the unstructured, time
\naccurate CFD flow-solver Tau is coupled with a computational module solving the flight-mechanic
\nequations of motion. By use of an overlapping grid technique (chimera), simulations of a complex
\nconfiguration with movable control-surfaces is possible.
\nResults of static calculations are presented to show the basic aerodynamics of the vortex dominated flowfield
\nof the delta wing. The static simulation cases also serve as starting solutions for the unsteady
\nsimulations. Results of the unsteady manoeuvre simulations are divided into guided motion and freeflight
\nmotion. For the guided motion an oscillating motion with a given frequency and amplitude is
\npresented. For the free-flight motion, the following cases are presented: free-to-roll from a non-zero
\ninitial roll-angle (without flap deflection), and free-to-roll initiated by flap deflection from an initial rollangle
\nof zero. These calculations demonstrate the functionality of the simulation system.
\nA 65-degree cropped delta wing model, with fuselage and movable trailing edge flaps, is used to gather
\nexperimental data. Several forced and free-to-roll experiments around the body fixed axes, both with and
\nwithout flap deflection, are performed in order to validate the computational results obtained with the
\nsimulation tool.