Prof. Dr. Joachim Peinke
Institute of Physics
AG Turbulence, Wind Energy and Stochastics – TWIST, Oldenburg
Phone: +49 (0)441-798-3536
Wind turbine blades face massive fluctuating loads which can lead to fatigue damages. Due to frequent changes in wind velocity and direction, the inflow of the blades is highly unsteady. Using numerical simulations and wind tunnel measurements, ForWind investigates the loads on the blades under various inflow conditions.
In order to investigate flow structures, methods of computational fluid dynamics (cfd) are increasingly used. ForWind calculates the interaction between the turbulent inflow and the blades. The time resolved methods which are applied, are mainly based on large eddy simulations (LES) or on direct numerical simulations (DNS). New high order methods to improve the accuracy of the calculations are being tested at ForWind as well.
Wind tunnel measurements
In the wind tunnel of the University of Oldenburg, ForWind measures lift and drag forces on airfoils, achieving Reynolds numbers up to 700.000 (approximately 50m/s).Forces acting on the airfoil are measured by pressure sensors. These measurements can be realised under fixed or under fast varying angles of attack. Especially the measurements at a varying angle of attack show a temporary increase in loads which is known as dynamic stall. Models of dynamic stall can therefore be developed or verified. Due to the sensitivity of the sensors, even the aerodynamic effects of small changes in surface roughness could be observed on airfoils under a steady angle of attack.
Furthermore, the wind tunnel offers many possibilities for measurements in an open or closed test section. For velocity measurements, different kinds of anemometers are available, e.g. hot wire or Laser-Doppler anemometers (LDA).