Analytical and experimental studies of the effect of geometric and aerodynamic variables on the performance of the Wells self-rectifying air turbine are presented in this paper. Two approaches to the prediction of the Wells turbine performance are described, both of which are based on the two dimensional cascade theory and isolated aerofoil data. Experimental results are based on the investigations in Unidirectional and oscillating airflow rigs.

Comparisons are made on the analytical and experimental results.

It is noted that the averaging technique of Beecham and Titchener, for obtaining approximate solutions to nonlinear, ordinary, differential equations, is not widely known or used. In its extended form, as given by Simpson and Ross it appears to offer a unified and useful approach to the solution of many dynamical and other problems. The present paper sets out to describe and discuss, through the medium of a collection of examples, the Beecham-Titchener-Simpson (BTS) method in an effort to encourage its more widespread use.

The method of images is used to calculate the analytical solution for an inviscid incompressible flow past four arbitrary circles which are then conformally mapped onto aerofoil sections. The analytical solution of the corresponding flow past the system of aerofoils is obtained and the pressure distributions about a particular three-element and a particular fourelement aerofoil are presented. These results are intended to be used to assess the accuracy of numerical methods.