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Author : Robert Rackl
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (123 download)
Download or read book Modeling of Turbulent Boundary Layer Surface Pressure Fluctuation Auto and Cross Spectra :. written by Robert Rackl and published by . This book was released on 2005 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : National Aeronautics and Space Administration (NASA)
Publisher : Createspace Independent Publishing Platform
ISBN 13 : 9781720629214
Total Pages : 88 pages
Book Rating : 4.6/5 (292 download)
Download or read book Modeling of Turbulent Boundary Layer Surface Pressure Fluctuation Auto and Cross Spectra - Verification and Adjustments Based on Tu-144ll Data written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-03 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: The literature on turbulent boundary layer pressure fluctuations provides several empirical models which were compared to the measured TU-144 data. The Efimtsov model showed the best agreement. Adjustments were made to improve its agreement further, consisting of the addition of a broad band peak in the mid frequencies, and a minor modification to the high frequency rolloff. The adjusted Efimtsov predicted and measured results are compared for both subsonic and supersonic flight conditions. Measurements in the forward and middle portions of the fuselage have better agreement with the model than those from the aft portion. For High Speed Civil Transport supersonic cruise, interior levels predicted by use of this model are expected to increase by 1-3 dB due to the adjustments to the Efimtsov model. The space-time cross-correlations and cross-spectra of the fluctuating surface pressure were also investigated. This analysis is an important ingredient in structural acoustic models of aircraft interior noise. Once again the measured data were compared to the predicted levels from the Efimtsov model.Rackl, Robert and Weston, AdamLangley Research CenterTU-144 AIRCRAFT; TURBULENT BOUNDARY LAYER; TUPOLEV AIRCRAFT; MATHEMATICAL MODELS; CIVIL AVIATION; PRESSURE; DATA PROCESSING; DATA REDUCTION; CROSS CORRELATION; AIRCRAFT NOISE; FLIGHT TESTS; POWER SPECTRA; FLIGHT ENVELOPES
Author : Nasa Technical Reports Server (Ntrs)
Publisher : BiblioGov
ISBN 13 : 9781289158422
Total Pages : 92 pages
Book Rating : 4.1/5 (584 download)
Download or read book Modeling of Turbulent Boundary Layer Surface Pressure Fluctuation Auto and Cross Spectra, Verification and Adjustments Based on Tu-144ll Data written by Nasa Technical Reports Server (Ntrs) and published by BiblioGov. This book was released on 2013-07 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt: The literature on turbulent boundary layer pressure fluctuations provides several empirical models which were compared to the measured TU-144 data. The Efimtsov model showed the best agreement. Adjustments were made to improve its agreement further, consisting of the addition of a broad band peak in the mid frequencies, and a minor modification to the high frequency rolloff. The adjusted Efimtsov predicted and measured results are compared for both subsonic and supersonic flight conditions. Measurements in the forward and middle portions of the fuselage have better agreement with the model than those from the aft portion. For High Speed Civil Transport supersonic cruise, interior levels predicted by use of this model are expected to increase by 1-3 dB due to the adjustments to the Efimtsov model. The space-time cross-correlations and cross-spectra of the fluctuating surface pressure were also investigated. This analysis is an important ingredient in structural acoustic models of aircraft interior noise. Once again the measured data were compared to the predicted levels from the Efimtsov model.
Author : Robert G. Rackl
Publisher :
ISBN 13 :
Total Pages : 77 pages
Book Rating : 4.:/5 (695 download)
Download or read book Modeling of Turbulent Boundary Layer Surface Pressure Fluctuation Auto and Cross Spectra written by Robert G. Rackl and published by . This book was released on 2005 with total page 77 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Brian E. McGrath
Publisher :
ISBN 13 :
Total Pages : 134 pages
Book Rating : 4.:/5 (317 download)
Download or read book Some Features of Surface Pressure Fluctuations in Turbulent Boundary Layers with Zero and Favorable Pressure Gradients written by Brian E. McGrath and published by . This book was released on 1987 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author :
Publisher :
ISBN 13 :
Total Pages : 16 pages
Book Rating : 4.:/5 (317 download)
Download or read book Turbulent Wall-Pressure Fluctuations: New Model for Off-Axis Cross-Spectral Density written by and published by . This book was released on 1996 with total page 16 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Sheldon Gardner
Publisher :
ISBN 13 :
Total Pages : 33 pages
Book Rating : 4.:/5 (227 download)
Download or read book Surface Pressure Fluctuations Produced by Boundary Layer Turbulence written by Sheldon Gardner and published by . This book was released on 1963 with total page 33 pages. Available in PDF, EPUB and Kindle. Book excerpt: Surface pressure fluctuations produced by boundary layer turbulence developed above a rigid plane surface are investigated theoretically. For an incompressible flow which obeys the Navier-Stokes equations, the boundary pressure is determined by a volume integration over quadrupole sources. Three different classes of source terms may be identified. These involve second, third, and fourth order velocity correlations. The contribution of the fourth order or turbulence-turbulence terms to the boundary pressure cross spectral density at high frequencies is obtained. The results show that the turbulence-turbulence boundary pressure sources are located at an effective height, and travel with an effective convection speed, both of which depend upon frequency and the shape of the mean velocity profile. At high frequencies, the pressure spectrum is found to be roughly proportional to the sixth power of the free stream velocity, and to the inverse cube of the frequency. Finally, the effect of the finite size of the transducer upon the measured boundary pressure spectrum is discussed. (Author).
Author : Song Fu
Publisher : Springer Nature
ISBN 13 : 9819739985
Total Pages : 1975 pages
Book Rating : 4.8/5 (197 download)
Download or read book 2023 Asia-Pacific International Symposium on Aerospace Technology (APISAT 2023) Proceedings written by Song Fu and published by Springer Nature. This book was released on with total page 1975 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : John H. Linebarger
Publisher :
ISBN 13 :
Total Pages : 288 pages
Book Rating : 4.:/5 (322 download)
Download or read book Computation of the Spectra of Turbulent Boundary Layer Surface- Pressure Fluctuations written by John H. Linebarger and published by . This book was released on 1972 with total page 288 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Stephen Anthony Rizzi
Publisher :
ISBN 13 :
Total Pages : 208 pages
Book Rating : 4.:/5 (317 download)
Download or read book Flight Test Measurements From The Tu- 144LL Structure/Cabin Noise Experiment written by Stephen Anthony Rizzi and published by . This book was released on 2000 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Wolfgang Rodi
Publisher : Elsevier
ISBN 13 : 0080530958
Total Pages : 1011 pages
Book Rating : 4.0/5 (85 download)
Download or read book Engineering Turbulence Modelling and Experiments 6 written by Wolfgang Rodi and published by Elsevier. This book was released on 2005-05-05 with total page 1011 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings of the world renowned ERCOFTAC (International Symposium on Engineering Turbulence Modelling and Measurements). The proceedings include papers dealing with the following areas of turbulence: · Eddy-viscosity and second-order RANS models · Direct and large-eddy simulations and deductions for conventional modelling · Measurement and visualization techniques, experimental studies · Turbulence control · Transition and effects of curvature, rotation and buoyancy on turbulence · Aero-acoustics · Heat and mass transfer and chemically reacting flows · Compressible flows, shock phenomena · Two-phase flows · Applications in aerospace engineering, turbomachinery and reciprocating engines, industrial aerodynamics and wind engineering, and selected chemical engineering problems Turbulence remains one of the key issues in tackling engineering flow problems. These problems are solved more and more by CFD analysis, the reliability of which depends strongly on the performance of the turbulence models employed. Successful simulation of turbulence requires the understanding of the complex physical phenomena involved and suitable models for describing the turbulent momentum, heat and mass transfer. For the understanding of turbulence phenomena, experiments are indispensable, but they are equally important for providing data for the development and testing of turbulence models and hence for CFD software validation. As in other fields of Science, in the rapidly developing discipline of turbulence, swift progress can be achieved only by keeping up to date with recent advances all over the world and by exchanging ideas with colleagues active in related fields.
Author :
Publisher :
ISBN 13 :
Total Pages : 0 pages
Book Rating : 4.:/5 (946 download)
Download or read book Three-Dimensional Correlation and Spectral Functions for Turbulent Velocities in Homogeneous and Surface-Blocked Boundary Layers written by and published by . This book was released on 1997 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: A pair of three-dimensional (3D) models for correlation functions and spectra of velocity fluctuations in turbulent boundary layers is presented. First, the case of homogeneous turbulence is considered. Von Karman's energy spectrum is used to develop a complete set of 3D correlation and spectral equations. Second, it is shown how the homogeneous spectra can be modified to include the effect of eddy-blocking at the ground. Assuming that the disturbance to the turbulent flow resulting from the blocking is irrotational, an equation is developed that allows one to write the vertically inhomogeneous, 2D cross spectra as a function of the 2D cross spectra for a homogeneous flow. Although there are only two adjustable parameters in the inhomogeneous model, the variance and a length scale, the model is shown to agree quite well with a variety of previous results for the atmospheric convective boundary layer (CBL).
Author : M. V. Lowson
Publisher :
ISBN 13 :
Total Pages : 36 pages
Book Rating : 4.:/5 (31 download)
Download or read book Pressure Fluctuations in Turbulent Boundary Layers written by M. V. Lowson and published by . This book was released on 1965 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author :
Publisher :
ISBN 13 :
Total Pages : 78 pages
Book Rating : 4.:/5 (227 download)
Download or read book Calculation of Turbulent Boundary Layer Wall Pressure Spectra written by and published by . This book was released on 1993 with total page 78 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study is an investigation into the suitability of various wavevector-frequency models of turbulent boundary layer wall pressure fluctuations for the prediction of experimental measurements of turbulent boundary layer wall pressure spectra. Three separate models of the wavevector- frequency spectrum proposed by D.M. Chase in 1980 and 1987 are evaluated. The wavevector-frequency spectral models are integrated numerically using a formulation for the point wall pressure spectrum (based on the work of Uberoi and Kovasznay). The representation of the wall pressure spectrum used accounts for the effect of a finite sized transducer on the measured wall pressure spectrum. By accounting for the area averaging effect of finite sized transducers on the measured turbulent boundary layer wall pressure spectra, it was possible to use Chase's rigorous formulations for the wavevector-frequency spectrum instead of the point pressure spectrum representations which assume an infinitely small measurement sensor. Results from the numerical integrations are compared to recent experimental data to determine which model of the wavevector- frequency spectrum most accurately predicts measured turbulent boundary layer wall pressure spectra. Data from experiments using fluids with a wide range of physical properties (air, water, and glycerine) are used for comparison purposes. Using the selected model, new empirical constants are established for use in the model for each fluid under consideration. Justification for use of the new empirical constants is given, and current limitations of the wavevector- frequency models are discussed.
Author : Kizhanatham Raghavachary Raman
Publisher :
ISBN 13 :
Total Pages : 100 pages
Book Rating : 4.:/5 (31 download)
Download or read book A Study of Surface Pressure Fluctuations in Hypersonic Turbulent Boundary Layers written by Kizhanatham Raghavachary Raman and published by . This book was released on 1974 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Ehssanollah F. Arman
Publisher :
ISBN 13 :
Total Pages : 154 pages
Book Rating : 4.:/5 (155 download)
Download or read book Simulation of Atmospheric Boundary Layer Turbulence with Cross-spectrum and Large-scale Eddy Structure written by Ehssanollah F. Arman and published by . This book was released on 1986 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Author : Tuncer Cebeci
Publisher : Elsevier
ISBN 13 : 0323151051
Total Pages : 423 pages
Book Rating : 4.3/5 (231 download)
Download or read book Analysis of Turbulent Boundary Layers written by Tuncer Cebeci and published by Elsevier. This book was released on 2012-12-02 with total page 423 pages. Available in PDF, EPUB and Kindle. Book excerpt: Analysis of Turbulent Boundary Layers focuses on turbulent flows meeting the requirements for the boundary-layer or thin-shear-layer approximations. Its approach is devising relatively fundamental, and often subtle, empirical engineering correlations, which are then introduced into various forms of describing equations for final solution. After introducing the topic on turbulence, the book examines the conservation equations for compressible turbulent flows, boundary-layer equations, and general behavior of turbulent boundary layers. The latter chapters describe the CS method for calculating two-dimensional and axisymmetric laminar and turbulent boundary layers. This book will be useful to readers who have advanced knowledge in fluid mechanics, especially to engineers who study the important problems of design.
