Studies of Slotted-Wall Interference using an Electrical Analogue. Part I. The Electrical Analogue to Steady and Oscillating Flow in Slotted-Wall Tunnels. Part II. Particular Examples of Slotted-Wall Tunnel Interference in Steady Flow.

Abstract

Part I of this report describes a study of the lift interference effect in slotted-wall wind tunnels performed by a pure resistance electrical analogue. Both steady and oscillatory flow are considered. Special techniques devised to represent the singular behaviour of a point wing and at the edges of each slot are discussed in detail. Comparisons are made with an exact solution based on an equivalent homogeneous boundary condition for steady flow. For oscillatory flow experimental results are presented which show how the magnitude of the interference upwash changes with the frequency of the oscillation. In Part II the electrical analogue computer is used to obtain results for two particular steady flow problems. The first involves a comparison between actual slotted walls and an equivalent homogeneous condition. In the second the lift interference for tunnels with all four walls slotted is examined.