On the evaluation of wall interference in two-dimensional ventilated wind tunnels by subsonic linear theory

Abstract

The interference potentials for lift, solid blockage and wake blockage have previously been presented in the form of integral expressions. In this Report the expression for wake blockage, which has been in error, is corrected, and the integral expressions are converted into power series. The series for wake blockage do not appear to have been given before, and the series for slotted walls also appear to be new. The motivation was to provide far-field boundary conditions, especially at large distances downstream, for computations of transonic flows within wind tunnels. Additionally these power series facilitate the calculation of the interference in the neighbourhood of the model. As an aid to the user the effects of parametric variations of wall porosity and slot geometry are demonstrated. Lift and blockage interference velocities, their streamwise gradients, and wall conditions for zero solid blockage are presented in both tabular and graphical form.