Wind tunnel
open type

CTO S.A. designs and manufactures custom-made open type wind tunnels

to exact meet your requirements.


Open type wind tunnels are characterized by the fact that air is sucked in from the laboratory environment, passes through the test section and is returned to the laboratory through the tunnel outlet.


The velocity distribution in open type wind tunnels is homogeneous in the range of 3 to 5%, while the angle of the jet deflection can be ± 2-3 °. The critical Reynolds number for a sphere in this type of tunnel is about 200,000, which corresponds to a turbulence intensity of about 1.5%.

Velocity distribution and flow slope in open circuit tunnels can be improved and turbulence levels reduced by using a contraction with high contraction coefficient and installing a velocity field settling section with a honeycomb straightener and net/nets inside.


Each open type wind tunnel designed and manufactured by us is „tailor-made” we can adjust its geometry and structure to virtually any location, even one to which access is limited or the dimensions of the room are small.

Remember, CTO S.A. meet your expectations.
Contact us and we will help you choose the right tunnel.


Characteristic parameters of the open type wind tunnels designed by CTO S.A:

  • air velocity range – defined by the customer (from 0.1 m/s up),
  • turbulence intensity – defined by the customer (from 0.2%),
  • contraction coefficient k = 9 or other highest achievable.

The air quality in the test section is correlated with the size of the available room and the possibility of using a sufficiently long section for determining the velocity field or the contraction coefficient, as well as the availability of power in the laboratory.

Contact one of our engineers for more information and a quote.
Prepare the input data that will help us choose the right tunnel.


  • velocity range in the test section,
  • the expected level of turbulence intensity in the test section,
  • the size of the largest element that will be tested in the test section,
  • climatic conditions in the laboratory,
  • power available in the laboratory,
  • laboratory dimensions,
  • the size of the access roads (entrances to the room).

See data sheets Open type wind tunnels.


Remember, CTO S.A. meet your expectations. Contact us and we will help you choose the right tunnel.
More information on the construction of an open type tunnel, the differences between open and closed tunnels, as well as the differences between the open and closed test section can be found in the Knowledge Base website tab.

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ul. Szczecińska 65
80-392 Gdańsk