How the wind tunnel looks


The Poul la Cour Tunnel is a wind tunnel of the closed-return type. It is one of the biggest university wind tunnels in the World with a fan driven by a 2.4 MW motor, giving a volume flow up to 630 cubic meter per second corresponding to a maximum test section velocity of about 105 m/s or 378 km/h.The maximum Reynolds number per meter is 7 million. Thus, for the standard two-dimensional wing sections with a chord length of 1.0 m the maximum Reynolds number will be 7 million. In special cases the chord length can be up to 2.0 m doubling the maximum Reynolds number to 14 million. 


The test section has two different configurations for the walls: The hard wall configuration that ensures precise aerodynamic tests and the Kevlar wall configuration that provides the possibility of noise measurements, where sound waves can pass from the wind tunnel model through the Kevlar cloth. The test section is surrounded by an anechoic chamber that allows sound measurements down to 100Hz. The corner vanes bending the flow around the four corners of the wind tunnel contain sound-absorbing material and along with the sound-absorbing material in the nose and tail cone of the fan dampen the sound from the 4.7 m diameter fan.

The contraction ratio of 1:9 ensures low turbulence intensity in the test section of around 0.1%. The test section has a cross-sectional area of 6.0 square meters based on a rectangular shape with a width of 3.0m, a height of 2.0m and a length of 9.0m. Two turntables flush with the test-
section floor and ceiling provide positioning of the model with a precision of 0.01 degrees and attachment for two-dimensional or three-dimensional models.

The standard wind tunnel testing equipment consists of pressure scanners consisting of 6 times 64 pressure transducers corresponding to 384 pressure signals used in the wind tunnel model, the walls and in the wake rake mounted at the downstream part of the test section. Further to this, there is a 3-component force balance in the turntable and miscellaneous sensors for pressure, temperature and relative humidity. For flow visualization purposes, an infrared camera system is available. Data is recorded and stored in a standard data-base format.



Test section

  • Width: 3.0 metres
  • Height: 2.0 metres
  • Length: 9 metres
  • Maximum wind speed: 105 m/s (378 km/h)
  • Turbulence intensity: < 0.1%
  • Low background noise
  • Re number/m: 7 million


  • Area: 2200 square metres
  • Fan diameter: 4.7 metres
  • Fan power: 2.4 MW
  • Maximum wind speed: 105 m/s or 378 km/h, corresponding to three times the speed of a hurricane


  • Pressure scanners with 384 sensors
  • Lift measurements using pressure measurements on airfoil, the wind tunnel wall and/or force gauges on shafts
  • Drag measurements using a wake rake
  • Noise measurements using an array of 84 microphones to focus on noise sources
  • Turntable with precise positioning of angle of attack
  • Miscellaneous sensors
13 APRIL 2021