[PDF] Experimental Cavity Pressure Measurements At Subsonic And Transonic Speeds Static Pressure Results eBook

Author : National Aeronautics and Space Adm Nasa
Publisher :
Page : 80 pages
File Size : 23,89 MB
Release : 2018-11-06
Category :
ISBN : 9781730884757

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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...

Author : National Aeronautics and Space Adm Nasa
Publisher :
Page : 84 pages
File Size : 49,62 MB
Release : 2018-11-10
Category :
ISBN : 9781730955280

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An experimental investigation was conducted to expand the data base and knowledge of flow fields in cavities over the subsonic and transonic speed regimes. A rectangular, 3-D cavity was tested over a Mach number range from 0.30 to 0.95 and at Reynolds numbers per foot from 1 x 10 to the 6th power to 4.2 x 10 to the 6th power. Two sizes of cavities were tested with length-to-height ratios (l/h) of 4.4 and 11.7 and with rectangular and nonrectangular cross-sections. Extensive static pressure data on the model walls were obtained and a complete tabulation of the data are presented. The boundary layer approaching the cavity was turbulent and the thickness was measured with a total pressure rake. The static pressure measurements obtained with the deep cavity configuration (l/h = 4.4) at Reynolds numbers greater than 3.0 x 10 to the 6th power per foot showed large fluctuations during the data sampling time. For the deep cavity, at lower Reynolds numbers, and for all conditions tested with the shallow cavity, the data showed much less unsteadiness. Though mean static pressure distributions have been used in past cavity analysis at transonic free stream conditions, the data presented here indicates that it is necessary to consider the instantaneous pressure distributions. The data also indicated that the shallow cavity static pressure measurements were sensitive to the thickness of the boundary layer entering the cavity. Plentovich, E. B. Langley Research Center...

Author : Gullapalli Sivaramakrishna
Publisher : Springer Nature
Page : 633 pages
File Size : 43,62 MB
Release : 2022-07-23
Category : Technology & Engineering
ISBN : 9811923787

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This book presents the select proceedings of the 3rd National Aerospace Propulsion Conference (NAPC 2020). It discusses the recent trends in the area of aerospace propulsion technologies covering both air-breathing and non-air-breathing propulsion. The topics covered include state-of-the-art design, analysis and developmental testing of gas turbine engine modules and sub-systems like compressor, combustor, turbine and alternator; advances in spray injection and atomization; aspects of combustion pertinent to all types of propulsion systems and nuances of space, missile and alternative propulsion systems. The book will be a valuable reference for beginners, researchers and professionals interested in aerospace propulsion and allied fields.