Dresden 2011 – wissenschaftliches Programm

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DY: Fachverband Dynamik und Statistische Physik

DY 34: Fluid Dynamics and Turbulence II

DY 34.7: Vortrag

Donnerstag, 17. März 2011, 15:45–16:00, ZEU 255

Stochastic modeling of lift dynamics under turbulent conditions — •Muhammad Ramzan Luhur, Patrick Milan, Jörge Schneemann, Matthias Wächter, and Joachim Peinke — ForWind, Centre for Wind Energy Research, University of Oldenburg, D-26111, Germany.

This paper presents stochastic modeling of the lift dynamics of an airfoil placed in turbulent inflows. The measurements were taken in the closed wind tunnel of the University of Oldenburg, for an airfoil FX 79-W-151A. The turbulent flows were generated using different grids including a fractal one, installed in front of the wind tunnel test section nozzle. The measurements were performed by two methods i.e. using force sensors and wall pressure sensors. The force sensors were installed at the two ends of an airfoil in the flap-wise direction and the pressure sensors at the test section walls.

For the stochastic modeling of the lift dynamics, force measurements with the fractal grid are used here because the force sensors give better results than the pressure sensors. The modeling of the lift coefficient is based on measurement time series of lift coefficient. This is done using a first-order stochastic differential equation called the Langevin equation. The results are optimized using a chi-square test on the probability distribution functions. The modeled time series and their probability distribution functions show good agreement with the actual measurement. The model is being developed with the aim to integrate it into a general wind energy converter model.