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Accession Number N14-0003935
Title Investigation of Materials for Boundary Layer Control in a Supersonic Wind Tunnel.
Publication Date Nov 2013
Media Count 24p
Personal Author A. Braafladt J. M. Lucero S. M. Hirt
Abstract During operation of the NASA Glenn Research Center 15- by 15-Centimeter Supersonic Wind Tunnel (SWT), a significant, undesirable corner flow separation is created by the three-dimensional interaction of the wall and floor boundary layers in the tunnel corners following an oblique-shock/ boundary-layer interaction. A method to minimize this effect was conceived by connecting the wall and floor boundary layers with a radius of curvature in the corners. The results and observations of a trade study to determine the effectiveness of candidate materials for creating the radius of curvature in the SWT are presented. The experiments in the study focus on the formation of corner fillets of four different radii of curvature, 6.35 mm (0.25 in.), 9.525 mm (0.375 in.), 12.7 mm (0.5 in.), and 15.875 mm (0.625 in.), based on the observed boundary layer thickness of 11.43 mm (0.45 in.). Tests were performed on ten candidate materials to determine shrinkage, surface roughness, cure time, ease of application and removal, adhesion, eccentricity, formability, and repeatability. Of the ten materials, the four materials which exhibited characteristics most promising for effective use were the heavy body and regular type dental impression materials, the basic sculpting epoxy, and the polyurethane sealant. Of these, the particular material which was most effective, the heavy body dental impression material, was tested in the SWT in Mach 2 flow, and was observed to satisfy all requirements for use in creating the corner fillets in the upcoming experiments on shock-wave/boundary-layer interaction.
Keywords Boundary layer control
Boundary layer separation
Corners
Eccentricity
Fillets
Materials tests
Reynolds number
Shock wave interaction
Supersonic wind tunnels
Surface roughness
Wind tunnel tests


 
Source Agency National Aeronautics and Space Administration
NTIS Subject Category 51A - Aerodynamics
51C - Aircraft
51F - Test Facilities & Equipment
Corporate Author Minnesota Univ., Minneapolis.
Document Type Technical report
Title Note N/A
NTIS Issue Number 1421
Contract Number N/A

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