Axisymmetric turbulent boundary layer on the cylindrical portion of an afterbody test model

Krishnan, V (1986) Axisymmetric turbulent boundary layer on the cylindrical portion of an afterbody test model. In: 15th International Symposium on Space Technology and Science, 19-23 May 1986, Tokyo, Japan.

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Abstract

This paper describes the results of experiments conducted to study the characteristics of an incompressible axisymmetric turbulent boundary layer on the cylindrical portion of an afterbody test model having a circular arc forebody and an afterbody in the presence of a high pressure cold air jet issuing from its base. Tests were conducted on an 80-mm maximum diameter model at the freestream velocities (jet off) of 12.8 and 21.5 m/sec and at jet pressure ratios of 1.0 (jet-off),1.26 and 1.54. Measurements include boundary layer profiles at four stations on the central cylindrical portion, and pressure distribution on the afterbody. The boundary layer grows in the axial direction, and the boundary layer parameters depend upon the test conditions and the measurement station. The variation of the shape factor is small. There13; is a slight decrease of the skin friction in the flow direction. The velocity profiles show substantial amount of the logarithmic region when plotted in the two-dimensional wall law and the defect law co-ordinates. The slope 'A' is approximately equal to 5.5, but the intercepts B and D depend upon the test conditions and the measurement station. The wake factor decreases in the presence of the jet.

Item Type: Conference or Workshop Item (Paper)
Uncontrolled Keywords: Aerodynamic drag;Afterbodies;Air jets;Axisymmetric flow;Incompressible boundary layer;Turbulent boundary layer;Cylinders;Flow distribution;Pressure gradients;Wind tunnel tests
Subjects: ENGINEERING > Fluid Mechanics and Thermodynamics
Division/Department: Fluid Dynamics
Depositing User: M/S ICAST NAL
Date Deposited: 14 Jan 2008
Last Modified: 24 May 2010 09:55
URI: http://nal-ir.nal.res.in/id/eprint/4317

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