Accession Number:

ADA067084

Title:

Jet Simulation Techniques: Simulation of Temperature Effects by Altering Gas Composition

Descriptive Note:

Final rept. 1 Oct 1976-30 Sept 1977

Corporate Author:

ARO INC ARNOLD AFS TN

Personal Author(s):

• Peters, W. L.

Report Date:

1979-03-01

Pagination or Media Count:

115.0

Abstract:

The objective of this investigation was to evaluate the effects of individual jet exhaust properties on afterbody drag coefficient and to determine whether these properties affect drag by primarily altering the jet plume shape andor jet entrainment. A large reduction in afterbody drag coefficient was observed with a decrease in the specific heat ratio at most underexpanded nozzle flow conditions. Regardless of free-stream Mach number of afterbody external configuration, an increase in the gas constant produced a consistent reduction in afterbody drag coefficient that was not a function of nozzle pressure ratio. The effects of gas constant increased for separated afterbody configurations and at transonic free-stream Mach numbers. From analysis of the experimental data, it was concluded that the effects of gas constant and specific heat ratio were, to a large extent separate, that the gas constant affected afterbody drag solely through the extrainment or mixing process, and that the specific heat ratio affected the drag primarily through determination of the inviscid jet plume shape.

Descriptors:

• *AERODYNAMIC DRAG
• *BOATTAIL AFTERBODIES
• *EXHAUST PLUMES
• *JET FLOW
• COMPOSITION(PROPERTY)
• ENTRAINMENT
• GASES
• INVISCID FLOW
• MODIFICATION
• RATIOS
• SHAPE
• SIMULATION
• SPECIFIC HEAT
• THERMAL PROPERTIES
• VARIATIONS
• WIND TUNNEL TESTS

Subject Categories:

• Fluid Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE