Sonderforschungsbereich
Beeinflussung komplexer turbulenter Scherströmungen

Numerical Study of Separation Control by Movable Flaps

Markus Schatz, Ulf Bunge, Holger Lübcke

Technische Universität Berlin
Hermann-Föttinger-Institut für Strömungsmechanik

Fachgebiet: CFD
Prof. Dr.-Ing. F. Thiele

Objectives

During the landing approach the feathers on the upper surface of bird wings tend to pop up, which can be interpreted as a biological high-lift device. Experimental studies of Meyer and Bechert, 1998, show that feather-like movable flaps on the upper surface of a laminar airfoil can increase lift and reduce drag at high angles of attack. For a better understanding, the effect of self-activated movable flaps is investigated by a numerical simulation of an airfoil with flap at different angles. Similar to the experiments, the numerical study considers an HQ17 airfoil at Re = 106.
HQ17 airfoil with movable flap (Re = 10^6) HQ17 airfoil with movable flap (Re=106)
Skua at high-lift condition with lifted feathers on the wing surface, 80k download
Skua at high-lift condition with lifted feathers on the wing surface
(Photo Rechenberg)
The numerical method used is based on a two- dimensional incompressible Finite-Volume scheme to solve the Reynolds-averaged Navier-Stokes equations. In previous investigations of unsteady turbulent flows, improved one- and two-equation models exhibited the best performance. Therefore, turbulence effects are modelled by the Spalart-Allmaras model as well as the LLR k- model.

1 2 3 4


Webmaster
Last modified: Wed Jul 26 19:04:03 CEST 2000