A simulation technique has been developed to analyze the testing environment of practical three-dimensional subsonic wind tunnels. By using a higher-order panel method, the present technology can simulate interference effects due to various geometrical features that are ignored in most previously published approaches. Among them are the effects of the three-dimensional test sections, the finite test section length, the corner fillet, the model size and location, the model mounting system, and instrumentation. Results for different wind tunnel environments are presented to demonstrate their significance on the wind tunnel interference. The present technique provides a diagnostic tool for the interpretation of experimental data and an effective means for designing a test environment with minimum interference.

Numerical Simulation of the Wind Tunnel Environment by a Panel Method

A combined analytical/experimental program for development of an improved slotted wind-tunnel wall representation is described. The effort is scheduled for completion in 1977. The vortex-lattice technique which is being used as the primary analytical tool for representing both the wind-tunnel and the lifting model is discussed. Comparisons of results obtained to date with available data are presented.

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Report on the status of a slotted wind tunnel wall representation using the vortex-lattice technique

Lift interference analysis on sweptback wing in rectangular wind tunnel test section with slotted side walls

Wind-tunnel lift interference on sweptback wings in rectangular test sections with slotted side walls

: A vortex lattice method has been applied to the problem of predicting the interference induced by ventilated wind tunnel walls. The formulations of both perforated and slotted wall boundaries using the vortex lattice method are presented. Wall interference effects on a single lifting line vortex for several basic wind tunnel test section configurations are compared with other theoretical results. Use of the vortex lattice method to calculate the aerodynamic characteristics of a lifting model too complex for exact analytical treatment is discussed. The surface pressure distribution on a combined wing and tail representation computed for a free stream is presented as well as those for both closed and slotted test sections to illustrate the capability of the technique.

W E Dietz

Papers

A Vortex Lattice Technique for Computing Ventilated Wind Tunnel Wall Interference