Which services does the facility offer

The Aeroacoustic Wind Tunnel (NLR-AWT) offers services for research into noise reduction techniques for making aircraft quieter. They can be performed during the early development stage (low TRL) or during improvement / upgrade programs. We also develop advanced measurement methods for locating and quantifying noise sources, and we map qualitative and quantitative complex air flows with various flow measurement techniques like (HFSB) PIV and hot wires.

The NLR-AWT is used for research into noise production of materials and shapes. The tunnel consists of a closed circuit that opens into the acoustic chamber, the ‘anechoic room’. This room is completely covered with foam wedges that absorb more than 99 per cent of all sound above lower bass notes (200 Hz). Typically scaled models are used in the wind tunnel, but also partial models can be applied, up to full scale. Projects performed include tests for developing advanced measurement techniques and landing gear and wind turbine noise in the open jet, as well as aerodynamic tests including probe calibrations in the closed test section.

Who can benefit from these services

Aircraft manufacturers and their suppliers, wind tunnel operators, SMEs, industry in other transport sectors like automotive, rail and maritime.

How to get access to the facility

The facility is located at NLR Marknesse. You will find the contact information on the right.

Detailed description of the facility

  • Closed circuit wind tunnel, powered by two 180kW axial fans, with open jet and closed test sections
  • Large anechoic room (9 x 8 x 6 m), completely covered with 0.5 m foam wedges yielding more than 99% absorption at above 200 Hz.
  • In the frequency range from 200 Hz to 20,000 Hz, the anechoic room is in accordance with ISO 3745:2017.
  • Wind speeds of up to 100 m/s can be achieved in the open jet configuration and up to 120 m/s in the closed test section 0.8×0.6 m2
  • The flow uniformity in the open jet is within 0.1% at the measurement location and turbulence intensity is in the order of 0.1%
  • Background Overall Sound Pressure Levels (OASPL) at 1m distance of the nozzle that are ranging from 58dB(A) at Ma=0.1 to 80dB(A) at M=0.2.
  • Low free stream turbulence level in the closed test section (0.01-0.02% @ 20 m/s, 0.02-0.03 @ 60 m/s and 0.04-0.06% @ 100 m/s).