Wall Corrections in Transonic Square Test Sections with Perforated Walls Influence of the Model Span on Lift Corrections,
FOREIGN TECHNOLOGY DIV WRIGHT-PATTERSON AFB OHIO
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The dimensions of models which are compatible with criteria such as the wall correction criteria can be tolerated compared with the measurement dispersions and only blockage corrections must be considered. For example, in a square test section with perforated horizontal walls, the obstructions which follow from the proposed criteria are 8 at Mach 0.95 and 1.3 at Mach 0.8. In the case of large span models, such obstruction values correspond to high ratios of the model span and section width. These ratios for a model type, such as the transonic transport having a span close to 7, are 0.65 at Mach 0.95 and 0.85 and Mach 0.80. Under these conditions, it is important to correctly describe the wing and, in particular, the lift distribution over the span in order to calculate the lift correction coefficients.
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