The designThe Lund wind tunnel can be tilted to simulate climbing flight and gliding flight, a feature which is extremely useful when studying conversion efficiency of fuel (the energy consumption of the bird is then measured in horizontal flight and with a small climbing angle), and the gliding flight performance.
The test section
The animal is trained to fly in the “test-section”, where the flow is near laminar (turbulence about 0.3-0.4%, expressed as variation around the mean flow). In the opening between the test section and the bellmouth the researcher operating the wind tunnel can have quick and easy access to the bird. The test section is encapsulated by a cage to prevent birds form escaping.
The wind tunnel building at the east entrance of the Ecology building, Lund University.
All kinds of animals is tested
Recently some attempts have been made using dung beetles in the wind tunnel. Since they are smaller than both bats and birds it is a challenge just to get them to fly stationary in the chamber.