Even modern computers are not able to handle complex flow situations  by numerical simulations. Thus many issues have to be studied with the  help of measurements using models. The wind tunnel of the University  of Oldenburg allows for many different experiments, e.g. wake  measurements of cylinders, investigate wind turbine and wind park  models or new kinds of anemometers. For this purpose, there is a  number of standard measurement techniques, like pressure probes, one  or multidimensional hot-wires or laser-Doppler anemometers.

Measurements addressing the acting forces on airfoils, represented by  lift and drag, are of special interest. This is achieved without  contact by obtaining the pressure distribution behind the airfoil and  over the wind tunnel walls. This also allows to analyse the forces  during a fast change in the angle of attack of the airfoil, which  generates strong short time fluctuations in the lift (dynamic stall).  There is a need for knowledge over this effect for adequate models.

	Schematic diagramm of lift under static and dynamic  changes in the angle of attack
	Picture of the closed test section mounted in the wind   tunnel of the University of Oldenburg.
	Comparison of lift measurements under static and dynamic  conditions.

Contact: Dr. Matthias Wächter      see also: