Suppression of Aerodynamically Induced Cavity Pressure Oscillations

Item

Title
Suppression of Aerodynamically Induced Cavity Pressure Oscillations
Date
1979
Index Abstract
Not Available
Photo Quality
Impossible
Report Number
AFFDL TR 79-3119
Corporate Author
Air Force Flight Dynamics Laboratory
Laboratory
Air Force Flight Dynamics Laboratory
Date Issued
1979-11
Extent
62
Identifier
ADA084897
Access Rights
Approved for public release; distribution unlimited
Distribution Classification
1
Contract
No contract - Laboratory Research
DoD Project
2401
DoD Task
240101
DTIC Record Exists
No
Distribution Change Authority Correspondence
None
Distribution Conflict
No
Abstract
A flight test program was performed to gain further insight into the phenomenon of flow-induced cavity pressure oscillations and to evaluate the effectiveness of suppression concepts in eliminating or reducing the pressure oscillations. The cavities tested were rectangular with approximate dimensions of 17 inches long, 8.5 inches deep, and 8.75 inches wide and were instrumented with microphones, static pressure ports, and a thermocouple. The flight speeds ranged from Mach number 0.6 to 1.3 at pressure altitudes of 3,000, 20,000, and 30,000 feet. The suppression devices included leading edge spoilers and deflectors and trailing edge ramps and deflectors. Several combinations of these were tested. The results indicate that the flow-induced pressure oscillations in a cavity of the dimensions tested and for the speed range tested can be significantly reduced with leading edge spoilers in conjunction with a trailing edge ramp. Reductions as large as 30 dB were achieved for the predominant model frequency for a one-third octave band. Other combinations of the suppression devices afforded some reduction, but the spoiler ramp combination proved most effective.
Report Availability
Full text available
Provenance
Bombardier/Aero
Type
report
Format
1 online resource
Creator
Shaw, Leonard L.
Media
AFFDLTR79-3119.pdf