An Investigation of Separated Flow about a Hemisphere-Cylinder at 0- to 19-Deg Incidence in the Mach Number Range from 0.6 to 1.5
Final rept. Oct 1974-Jun 1976
ARNOLD ENGINEERING DEVELOPMENT CENTER ARNOLD AFB TN
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A wind tunnel investigation was conducted of the separated flow about a hemisphere-cylinder at incidence from 0 to 19 deg in the Mach number range from 0.6 to 1.5. At zero incidence, a nose separation bubble is revealed from analysis of shadowgraphs and surface pressure distributions between Mach numbers 0.7 and 0.9. The basic differences between the present nose separation bubble and the leading-edge separation bubble of airfoils are discussed. A multiple shock system, consisting of a lambda shape shock and two normal shocks, prevails in the flow field as a result of the viscousinviscid interaction which is strongest at M at infinity 0.85. Velocity field measurements utilizing a laser velocimeters were obtained for M at infinity 0.85. The concept of an effective body and the particle dynamics are used to analyze the velocity. For incidences from 5 to 19 deg, shadowgraphs, surface pressures, and oil flow pictures showing the separation patterns and limiting streamlines were obtained through the Mach number range. Two separation regions, the nose separation bubble and the crossflow separation zone, were found to exist simultaneously. Concentrated vortices standing at the leeside forebody were found, and the mechanism and conditions for their appearance and discussed.
- Test Facilities, Equipment and Methods
- Fluid Mechanics