Time resolved identification of aerodynamic extreme events and unsteady effects under turbulent inflow conditions
Final Report Abstract
ln this project, an unique experimental Setup to investigate highly dynamic effects like dynamic stall without pitching the airfoil, but changing the inflow was developed. The corresponding 2D active grid was characterized in detail, allowing the generation of innumerable tailored inflow fields. The in-depth understanding of the emergent and imprinted structures enabled a detailed Interpretation of the resulting dynamic forces. Based on this the adaptive camber concept could be investigated successfully under a broad variety of inflows. The detailed measurements with PIV enabled the exact Interpretation of the interaction between inflow and aerodynamic response of the airfoil. Furthermore, the POD was used to attain an even more thorough Interpretation of the coherent structures and their influence on the forces could be achieved. This better understanding of the mechanisms makes it possible to improve further adaptive or smart blade concepts in turbulent inflow. In addition to these positive achievements, the cooperation between Darmstadt and Oldenburg allowed the fundamental theories of Theodorsen, Sears and Atassi to be experimentally substantiated. Also the new approach of using the directed percolation theory to describe the laminar turbulent transition was confirmed experimentally for fundamental and generic flows. Starting from this the approach was expanded to more complex flows showing that the theory can also be used for the description for the onset of a laminar Separation bubble on the suction side of an airfoil. Furthermore, during the whole project the CFD simulations from Stuttgart gave a very detailed insight into the flow around the airfoil. This supported the evaluation of the measured PIV recordings enormously. The only setbacks here was that the CFD simulations could not be reconciled with the experimentally measured forces. The only project goal that could not be achieved was that the new manufactured ACP could not be used to test the adaptive camber concept for different configurations.
Publications
- Experimental investigation of Passive Load Reduction under dynamic inflow conditions, 33rd AIAA Applied Aerodynamics Conference (p. 3313), Dallas, Texas (2015)
U. Cordes, G. Kampers, C. Tropea, K. Hufnagel, J. Peinke
(See online at https://doi.org/10.2514/6.2015-3313) - Stochastic analysis of aerodynamic forces acting on a self-adaptive camber airfoil in turbulent inflow, 33rd AIAA Applied Aerodynamics Conference (p. 2427), Dallas, Texas (2015)
G. Kampers, U. Cordes, C. Tropea, J. Peinke, M. Holling
(See online at https://doi.org/10.2514/6.2015-2427) - Numerical and experimental investigation of an airfoil with load control in the wake of an active grid, Journal of Physics: Conference Series vol. 735, 022036 (2016)
A. Fischer, T. Lutz, E. Krämer, U. Cordes, K. Hufnagel, C. Tropea, G. Kampers, M. Holling, J. Peinke
(See online at https://doi.org/10.1088/1742-6596/753/2/022036) - Note on the limitations of the Theodorsen and Sears functions, J. Fluid Mech., vol. 811, R1, (2017)
U. Cordes, G. Kampers, T. Meißner, C. Tropea, J. Peinke and M. Holling
(See online at https://doi.org/10.1017/jfm.2016.780) - Percolation: Statistical description of a spatial and temporal highly resolved boundary layer transition, Progress in Turbulence VII, p. 11-16, (2017)
T. T. B. Wester, D. Traphan, G. Gülker, J. Peinke
(See online at https://doi.org/10.1007/978-3-319-57934-4_2) - Aerodynamics and Per colation: Unfolding Laminar Separation Bubble on Airfoils, Physical Review X 8, 021015 (2018)
D. Traphan, T. T. B. Wester, G. Gülker, J. Peinke, P. G. Lind
(See online at https://doi.org/10.1103/PhysRevX.8.021015) - High speed PIV measurements of an adaptive camber airfoil under highly gusty inflow conditions, Journal of Physics: Conference Series vol. 1037, 072007 (2018)
T. T. B. Wester, G. Kampers, G. Gülker, J. Peinke, U. Cordes, C. Tropea, M. Holling
(See online at https://doi.org/10.1088/1742-6596/1037/7/072007) - On the aerodynamic behavior of an airfoil under tailored turbulent inflow conditions, 5th International Conference on Experimental Fluid Mechanics ICEFM, Munich (2018)
D. Traphan, T. T. B. Wester, J. Peinke, G. Gülker
(See online at https://doi.org/10.18726/2018_2) - The Adaptive Camber Concept - A passive approach for gust load alleviation on wind turbines, Wind Energy, 1-13 (2018)
U. Cordes, B. Lambie, K.Hufnagel, H.Spiegelberg, G.Kampers, C.Tropea
(See online at https://doi.org/10.1002/we.2190) - Using high speed PIV measurements and POD to solve the mystery of dynamic stall, 19th International Symposium on Applications of Laser and Imaging Techniques to Fluid Mechanics, Lisbon (2018)
T. T. B. Wester, S. Bartholomay, D. Traphan, M. Holling, J. Peinke, G. Gülker
