Ohio State University Wind Tunnel Tests

Recognizing the need for a wind turbine airfoil performance data base, NREL, funded by the Department of Energy, awarded a contract to The Ohio State University to conduct a wind tunnel test program.

Background

Airfoils for wind turbines have been selected by comparing data from different wind tunnels, tested under different conditions. This makes it difficult to make accurate comparisons. Most wind tunnel data sets do not contain airfoil performance in stall, which is commonly experienced by turbines operating in the field. Wind turbines are often roughened by soiling, for which there is very little data. Tests have shown that dynamic stall is a common occurrence for most wind turbines operating in yawed, stalled, or turbulent conditions. Little dynamic stall data exists for the airfoils of interest to a wind turbine designer.

The Ohio State University Program

The Ohio State University program tested a series of popular wind turbine airfoils. A standard test matrix was developed to assure that each airfoil was tested under the same conditions. The test matrix was developed in partnership with industry and is intended to include all of the operating conditions experienced by wind turbines. These conditions include airfoil performance at high angles of attack, rough leading edges (bug simulation), and steady and unsteady angles of attack.

Special care has been taken to report as much of the test conditions and raw data as practical so that designers can make their own comparisons and focus on details of the data relevant to their design goals. Some of the airfoil coordinates are proprietary to industry partners. To protect the information that defines the exact shape of the airfoil, the coordinates have not been included in the report for non-NREL airfoils.