Design of Wind Tunnel Contractions: A Method Based on the Use of the Schwarz‐Cristoffel Transformation for Incompressible Inviscid Flow

Abstract

A method is given for the design of a two‐dimensional wind tunnel contraction for incompressible inviscid flow. The contraction is considered to join parallel channels of different width and is of finite length. The contraction boundary consists of two curved portions fairing smoothly into the channel walls at the upstream and downstream ends and a straight portion in between joining the other ends of Ihc curved portions. The shape of the boundary is determined by specifying: (i) constant velocities along the curved portions and (ii) the angle of inclination of the straight portion to the tunnel axis. The solution to the problem is obtained by working in the hodograph plane. For this purpose the contraction is considered to be made up of two distinct parts, upstream and downstream, and the solution is worked out for each separately. Results are given in tabular form for differing values of the above parameters (i) and (ii). It is hoped that the results will be found useful in the design of most low‐speed tunnels and particularly those with large contraction ratios. The results given here have been used in the design of a smoke tunnel (contraction ratio 15 to 1), a model of which has been built and tested with satisfactory results.

Citation

Jordinson, R. (1961), "Design of Wind Tunnel Contractions: A Method Based on the Use of the Schwarz‐Cristoffel Transformation for Incompressible Inviscid Flow", Aircraft Engineering and Aerospace Technology, Vol. 33 No. 10, pp. 294-297. https://doi.org/10.1108/eb033466