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Flow control in a diffusing S-DuctAccurate measurements have been made of secondary flow in a 1.51 area ratio diffusing 30 deg - 30 deg S-Duct with circulair cross section. Turbulent flow was entering the duct at Mach number of 0.6, the boundary layer thickness at the duct entrance was ten percent of the duct inlet diameter. Through measurements made, local flow velocity vector as well as static and total pressures mapping of the flow at several stations were obtained. Strong secondary flow was measured in the first bend which continued into the second bend with new vorticity produced in there in the opposite direction. Surface oil flow visualization and wall pressures indicated a region of separated flow starting at theta approximately equal to 22 deg on the inside of the first bend up to theta approximately equal to 44 deg on the outside of the second bend. The flow separated in 'cyclone' form and never reattached in the duct. As a result of the secondary flow and the flow separation, significant total pressure distortion was observed at the exit of the duct. Using flow control devices the separation was eliminated while the exit distortion was improved.
Document ID
19850043777
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Vakili, A. D.
(Tennessee Univ. Space Inst. Tullahoma, TN, United States)
Wu, J. M.
(Tennessee Univ. Space Inst. Tullahoma, TN, United States)
Liver, P.
(Tennessee Univ. Space Inst. Tullahoma, TN, United States)
Bhat, M. K.
(Tennessee, University Space Institute, Tullahoma, TN, United States)
Date Acquired
August 12, 2013
Publication Date
March 1, 1985
Subject Category
Aerodynamics
Report/Patent Number
AIAA PAPER 85-0524
Accession Number
85A25928
Funding Number(s)
CONTRACT_GRANT: NAG3-364
Distribution Limits
Public
Copyright
Other

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