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Experimental investigation of wall shock cancellation and reduction of wall interference in transonic testingA series of experiments were performed to evaluate the effectiveness of a three-dimensional land and groove wall geometry and a variable permeability distribution to reduce the interference produced by the porous walls of a supercritical transonic test section. The three-dimensional wall geometry was found to diffuse the pressure perturbations caused by small local mismatches in wall porosity permitting the use of a relatively coarse wall porosity control to reduce or eliminate wall interference effects. The wall porosity distribution required was found to be a sensitive function of Mach number requiring that the Mach number repeatability characteristics of the test apparatus be quite good. The effectiveness of a variable porosity wall is greatest in the upstream region of the test section where the pressure differences across the wall are largest. An effective variable porosity wall in the down stream region of the test section requires the use of a slightly convergent test section geometry.
Document ID
19760015070
Acquisition Source
Legacy CDMS
Document Type
Contractor Report (CR)
Authors
Ferri, A.
(General Applied Science Labs., Inc. Westbury, NY, United States)
Roffe, G.
(General Applied Science Labs., Inc. Westbury, NY, United States)
Date Acquired
September 3, 2013
Publication Date
January 1, 1975
Subject Category
Aerodynamics
Report/Patent Number
NASA-CR-144979
Accession Number
76N22158
Funding Number(s)
CONTRACT_GRANT: NAS1-13616
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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