The New Wind Tunnel

During the design process of the new boundary layer wind tunnel, the recommendations of the international literature, the experience of current and former colleagues of the Department of Fluid Mechanics and the opinions of multiple foreign experts were all taken into account.

According to these, the width of the wind tunnel test section has to be at least approximately 3 m wide. The so-called boundary layer generating section, where the roughness elements placed on the ground create a flow similar to the atmospheric boundary layer, should be at least 10 m long. This ensures that the gustiness of the created air flow and the size of the vortices are realistic on the planned model scale of 1:200.

The experience of personal visits to several wind tunnel laboratories abroad (University of Surrey, ETH Zürich /EMPA, KIT Karlsruhe, Universität Hamburg, TU Eindhoven) also had an effect on the design process. The specifications of wind tunnels which were constructed for building- and environmental aerodynamics measurements have been recently summarized.

Data of boundary layer wind tunnels built in the recent years or under construction

Based on the available literature, there are two wind tunnel configurations that seem to ensure the maximum range of applications:

  1. An open-circuit wind tunnel which uses the air inside the laboratory, but is also able to use external air due to optional openings on the laboratory walls (e.g. in case the tracer gas emitted in dispersion experiments needs to be cleared from the laboratory)
  2. A recirculating wind tunnel, in which the recirculated air can be changed again optionally, through openings.

Due to the available space in the building and the lower construction costs, we have chosen the first possibility. The planned layout of the wind tunnel is shown on the images below.

  • Test section size: 15 – 17 x 3 x 2 m
  • Full length: approx. 26 m
  • Maximum wind speed: 20-25 m/s
  • Fan power: 6 x 30 or 6 x 37 kW
Initial plan of the wind tunnel
Initial plan of the wind tunnel
Test section of the wind tunnel
Test section of the wind tunnel
Rendered image of wind tunnel (Initial plan)

During the design process, we will rely on our experience from the smaller wind tunnels designed at the Department of Fluid Mechanics, the solutions at the Gödöllő wind tunnel which was designed under the leadership of Dr. János Vad, and the construction methods seen in wind tunnels abroad, from which examples are shown below.

The boundary layer wind tunnel of Hamburg University is one of the biggest in Europe
The wind tunnel of the National Agriculture Research and Innovation Center (NAIK) in Gödöllő, planned under the leadership of Dr. János Vad and with the help of several researchers from BME
The new recirculating boundary layer wind tunnel of EMPA and ETH Zürich
The meteorological boundary layer wind tunnel of the University of Surrey in Guildford with a test section size of 20 x 3.5 x 1.5 m
The ”VW” wind tunnel of the Laboratory of Building- and Environmental Aerodynamics in Karlsruhe. Source: KIT Institut für Hydromechanik