Flow modulation by a mushroom-like coating around the separation region of a wind-turbine airfoil section
Abstract
The flow over a mushroom-shaped microscale coating was experimentally inspected over a diverging channel that followed the pressure side of a wind turbine blade (S835). High-resolution particle image velocimetry was used to obtain in-plane velocity measurements in a refractive-index-matching flume at Reynolds number Reθ ≈ 1200 based on the momentum thickness. The results show that the evolution of the boundary layer thickness, displacement thickness, and shape factor change with the coating, contrary to the expected behavior of an adverse pressure gradient boundary layer over a canonical rough surface. Comparison of the flow with that over a smooth wall revealed that the turbulence production exhibited similar levels in both cases, suggesting that the coating does not behave like a typical rough wall, which increases the Reynolds stresses. Proper orthogonal decomposition was used to decompose the velocity field to investigate the possible structural changes introduced by the wall region. It suggests that large-scale motions in the wall region lead to high-momentum flow over the coated case compared to the smooth counterpart. This unique behavior of this surface coating can be useful in wind-turbine applications, with great potential to increase the power production.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Jul 01, 2018
- Source ID
- 10.1063/1.5022819
Entities
People
- Ali Doosttalab
- Ali M Hamed
- Burak Aksak
- Humberto Bocanegra Evans
- Leonardo P Chamorro
- Luciano Castillo
- Murat Tutkun
- Serdar Gorumlu
- Suranga Dharmarathne
Organizations
- Division of Chemical, Bioengineering, Environmental, and Transport Systems
- Institute for Energy Technology
- Office of Naval Research
- Purdue University
- Texas Tech University
- Union College
- University of Illinois Department of Mechanical Science and Engineering
- University of Illinois Urbana–Champaign
- University of Oslo