Large-Scale Low Turbulence Subsonic wind Tunnel

A versatile classic semi-close wind tunnel for wind speeds up to 60m/s with low turbulence levels

Background 
Built in 1964 this is our oldest tunnel, it's a classical semi-closed loop tunnel and was the second large low-speed (L2) wind tunnel in the fluid dynamics lab. Today only the L2 remains of the two and has over the years been continuously developed and kept up with current technology. During the latest large overhaul in 2011, all control systems were digitized another traverse system added. Today this is our most versatile tunnel and used for a large variety of experiments does by far and exceeds all other with the number of projects. 
Description 
The tunnel operates at atmospheric pressure with a pressure recovery just downstream of the test section. A 170kw motor powers the circulation fan and a 80kW fan circles the cooling flow for controlling the temperature. During normal condition, the turbulence levels are below 0.1% but grids to increase this to 4% at the inlet can be installed. The test section can be accessed from all direction and the whole test section can be replaced if needed. There are several mounting points and traverse systems to hold geometries and measurement devices. A rolling floor with boundary layer suction can be installed for road vehicle studies. The wind tunnel system is controlled and monitored using Labview. An infrastructure for communication between systems is set up in the lab making it easy to add and combine different devices for a test campaign.
Instrumentation 
The test section/model can be installed with a large number of devices and depend on test campaign. The large pool of methods makes it possible for us to select the most suitable data acquisition system for the problem and have redundancy in measurements. As for now, the lab houses the following system ready to be used in the tunnel; 
  • Anemometry units: large variety of hot wires (multi-directional, boundary layer, high and low-speed response) and hot-films. 
  • Pressure: Multihole probes(standard + customized to project), Time-Resolved, Pressure scanner, High acracy manometers, Scanivavle system (stepping channel). 
  • Thermography (Time-Resolved IRT, LCT, TSP, Point) 
  • PIV (Stereo, Long-Distance, Micro, Tomo, Time-Resolved) 
  • Balance: Two six-axis balances + number of independent load cell. 
We can also accommodate different flow visualization techniques such as oil and smoke. 
Typical Research Topics: 
  • General Aerodynamic Model analysis; train, cameras, aircraft wind power plants
  • Boundary layer studies, control actuation, suction surface roughness
  • Analysis of road vehicles, platooning 
  • Analysis of Propeller Performance, counter-rotating and normal
  • Analysis of aerodynamics of infrastructure and buildings 
  • Fundamental fluid Dynamic Research 

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Published: Wed 03 Oct 2018.