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Natural laminar flow flight experiments on a swept wing business jet-boundary layer stability analysesThe linear boundary layer stability analyses and their correlation with data of 18 cases from a natural laminar flow (NLF) flight test program using a Cessna Citation 3 business jet are described. The transition point varied from 5% to 35% chord for these conditions, and both upper and lower wing surfaces were included. Altitude varied from 10,000 to 43,000 ft and Mach number from 0.3 to 0.8. Four cases were at nonzero sideslip. Although there was much scatter in the results, the analyses of boundary layer stability at the 18 conditions led to the conclusion that crossflow instability was the primary cause of transition. However, the sideslip cases did show some interaction of crossflow and Tollmien-Schlichting disturbances. The lower surface showed much lower Tollmien-Schlichting amplification at transition than the upper surface, but similar crossflow amplifications. No relationship between Mach number and disturbance amplification at transition could be found. The quality of these results is open to question from questionable wing surface quality, inadequate density of transition sensors on the wing upper surface, and an unresolved pressure shift in the wing pressure data. The results of this study show the need for careful preparation for transition experiments. Preparation should include flow analyses of the test surface, boundary layer disturbance amplification analyses, and assurance of adequate surface quality in the test area. The placement of necessary instruments and usefulness of the resulting data could largely be determined during the pretest phase.
Document ID
19860015188
Acquisition Source
Legacy CDMS
Document Type
Contractor Report (CR)
Authors
Rozendaal, R. A. (Boeing Commercial Airplane Co. Seattle, WA, United States)
Date Acquired
September 5, 2013
Publication Date
May 1, 1986
Subject Category
Aerodynamics
Report/Patent Number
NASA-CR-3975
NAS 1.26:3975
D6-53071
Accession Number
86N24659
Funding Number(s)
PROJECT: RTOP 506-61-41-02
CONTRACT_GRANT: NAG1-401
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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