Published online by Cambridge University Press: 04 July 2016
The aerodynamic characteristics of two-dimensional transient aerofoil motions in low-speed flows in a wind tunnel with either closed wall or open (jet) walls, including the effect of a downstream closed wall diffuser, have been investigated. The mathematical formulation for the aerofoil and its unsteady wake is based on linear theory and is solved by a piecewise linear vorticity method; the wall boundaries are represented by distributions of sources. Numerical calculations have been made for various values of tunnel height to chord ratio.
Interference effects on the rate of build up of lift to a steady state following a step change in incidence can be large, especially for open jet tunnels.