COMPUTATIONS OF THE VORTEX DEVELOPMENT FOR A STEADY AND UNSTEADY LAMBDA–WING WIND TUNNEL EXPERIMENT

Abstract

The focus of this paper is on the results of steady and unsteady aerodynamic computations for the design of the IWEX model (German for: Unsteady Vortex Experiment). The main character of the thickness caused vortex developing at the round leading edge of the lambda wing is analyzed. The experimental concept of the new test rig, the new wind tunnel walls and the half wing model is briefly described. The characteristics of the main and the smaller tip vortex are specified. The inboard movement of the main vortex with the angle of attack and the consequences for the suction peak and the load distribution is determined. As the whole free stream Mach number range of the test envelope from 0.3 – 0.7 was important for the structural design, transonic effects, especially shock - vortex interactions triggering vortex development, were studied. During the design of a peniche, the differences of the flow character to the reference results without wind tunnel walls were minimized. The effects of corner separation and displacement are specified at different stages of the iterative process. Finally, the basic unsteady results for a pitching motion are discussed, mainly considering global and distributed coefficients.