ABSTRACT
The power to drive a low-speed wind tunnel varies as the cube of the test-section velocity. From an operational point of view, wind tunnels are generally classified as low-speed, high-speed, and special purpose tunnels. In low-speed tunnels, the predominant factors influencing the tunnel performance are inertia and viscosity. High-speed tunnels are those with test-section speed more than 650 kmph. High-speed tunnels are generally grouped into intermittent and continuous operation tunnels, based on the type of operation. All modern wind tunnels have four important components; the effuser, the working or test-section, the diffuser, and the driving unit. In general, the effuser contains honeycomb and wire gauze screens to reduce the turbulence and produce a uniform air stream at the exit. The overall length of the wind tunnel may be shortened, and the rejection of kinetic energy at the diffuser exit eliminated, by the construction of some form of return circuit.
