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Part II: Steady aerofoil-spoiler characteristics

Published online by Cambridge University Press:  04 July 2016

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Summary

A surface singularity method has been formulated to predict two-dimensional spoiler characteristics at low speeds. Vorticity singularities are placed on the aerofoil surface, on the spoiler surface, on the upper separation streamline from the spoiler tip and on the lower separation streamline from the aerofoil trailing edge. The separation region is closed downstream by two discrete vortices. The flow inside the separation region is assumed to have uniform total head.

The downstream extent of the separated wake is an empirical input. The flows both external and internal to the separated regions are solved.

Theoretical results have been obtained for a range of spoiler-aerofoil configurations which compare reasonably with experimental results.

The model is deficient in that it predicts a higher compression ahead of the spoiler than obtained in practice. Furthermore, there is a minimum spoiler angle below which a solution is not possible; it is thought that this feature is related to the physical observation that at small spoiler angles, the separated flow from the spoiler reattaches on the aerofoil upper surface ahead of the trailing edge.

Type
Inviscid theory of two-dimensional aerofoil/ spoiler configurations at low speed
Information
The Aeronautical Journal , Volume 91 , Issue 908 , October 1987 , pp. 359 - 366
Copyright
Copyright © Royal Aeronautical Society 1987 

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