Author: Maureen B. TracyPublisher:
ISBN:
Category : Aerodynamics, Transonic
Languages : en
Pages : 84
Book Description
Cavity Unsteady-Pressure Measurements at Subsonic and Transonic Speeds
Author: Maureen B. TracyPublisher:
ISBN:
Category : Aerodynamics, Transonic
Languages : en
Pages : 84
Book Description
Experimental Cavity Pressure Measurements at Subsonic and Transonic Speeds. Static-pressure Results
Author: E. B. PlentovichExperimental Cavity Pressure Measurements at Subsonic and Transonic Speeds. Static-Pressure Results
Author: National Aeronautics and Space Administration (NASA)Publisher: Createspace Independent Publishing Platform
ISBN: 9781722386801
Category :
Languages : en
Pages : 80
Book Description
An experimental investigation was conducted to determine cavity flow-characteristics at subsonic and transonic speeds. A rectangular box cavity was tested in the Langley 8-Foot Transonic Pressure Tunnel at Mach numbers from 0.20 to 0.95 at a unit Reynolds number of approximately 3 x 10(exp 6) per foot. The boundary layer approaching the cavity was turbulent. Cavities were tested over a range of length-to-depth ratios (l/h) of 1 to 17.5 for cavity width-to-depth ratios of 1, 4, 8, and 16. Fluctuating- and static-pressure data in the cavity were obtained; however, only static-pressure data is analyzed. The boundaries between the flow regimes based on cavity length-to-depth ratio were determined. The change to transitional flow from open flow occurs at l/h at approximately 6-8 however, the change from transitional- to closed-cavity flow occurred over a wide range of l/h and was dependent on Mach number and cavity configuration. The change from closed to open flow as found to occur gradually. The effect of changing cavity dimensions showed that if the vlaue of l/h was kept fixed but the cavity width was decreased or cavity height was increased, the cavity pressure distribution tended more toward a more closed flow distribution. Plentovich, E. B. and Stallings, Robert L., Jr. and Tracy, M. B. Langley Research Center...
Three-dimensional Cavity Flow Fields at Subsonic and Transonic Speeds
Author: Elizabeth B. PlentovichPublisher:
ISBN:
Category :
Languages : en
Pages : 88
Book Description
Effect of Passive Venting on Static Pressure Distributions in Cavities at Subsonic and Transonic Speeds
Author: Robert L. Stallings (Jr.)Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Effect of sweep on cavity flow fields at subsonic and transonic speeds
Author: Characterization of Cavity Flow Fields Using Pressure Data Obtained in the Langley 0.3-Meter Transonic Cryogenic Tunnel
Author: Maureen B. TracyPublisher:
ISBN:
Category : Aerodynamics, Transonic
Languages : en
Pages : 40
Book Description
The Effect of Depth on a Three-dimensional Rectangular Cavity in Subsonic Flow
Author: Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
A cavity was inserted into a 20 m/s subsonic flow. The flow had a freestream turbulence level of 0.5%. The cavity had an aspect ratio of 2.0 and was capable of reaching depths from 0.0 to 2.35L. Velocity and turbulence measurements were acquired in the shear layer over the cavity and upstream of the cavity in the approaching boundary layer using hotwire anemometry. These measurements showed that the approaching boundary layer approximated a universal fully turbulent boundary layer. The hotwire was also used to acquire energy spectra in the boundary and free shear layers as well as in the freestream in order to examine the frequency content of the flow. Finally condenser microphones were installed into the cavity and used to acquire energy spectra by measuring the unsteady pressure inside the cavity at various locations. Significant effort was made to identify the causes for each mode. The author has found evidence to suggest that tones generated by the cavity can be driven either acoustically or fluid dynamically. However, acoustics appear to dominate in the current cavity geometry and the current flow speed. The data acquired agrees well with past experiments. However, several new trends were noted that the author has not found mentioned in past work. First, shear layer velocity and turbulence profiles indicate the presence of a recirculation region at the upstream cavity lip. Second, relative sound pressure levels indicate that the total energy inside the cavity decreases as depth increases from D/L = 0.5 to 2.1. This loss of energy coincides with an increase in energy in the shear and boundary layers at the same depths. However, at cavity depths greater than D/L = 2.1 the trend reverses itself as a second vortex cell begins to form beneath the primary vortex.
Scientific and Technical Aerospace Reports
Author: Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 602
Book Description
Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Cavity Aeroacoustics
Author: Richard E. DixPublisher:
ISBN:
Category : Aeroacoustics
Languages : en
Pages : 40
Book Description