Download or read book Low Wavenumber Levels of Turbulent Boundary Layer Wall Pressure Fluctuations in Zero and Adverse Gradients written by Mark Jay Moeller and published by . This book was released on 1978 with total page 87 pages. Available in PDF, EPUB and Kindle. Book excerpt: The low wavenumber components of the turbulent boundary layer wavenumber frequency spectrum of wall pressure fluctuations were measured with two flush-mounted rectangular plates having approximately clamped boundary conditions. The plates were designed to provide low wavenumber measurements at higher frequencies and wavenumbers than previous plate experiments in order to provide data comparable with measurements made by Farabee and Geib (7) with an array of flush-mounted microphones. The low wavenumber measurements were made in the M.I.T. low noise low turbulence subsonic wind tunnel under zero and adverse pressure gradient conditions. When nondimensionalized on outer boundary layer variables the adverse pressure gradient data do not exhibit increased levels from those of the zero pressure gradient data. The zero pressure gradient data are in good agreement with the levels reported by Farabeen and Geib (7) for the same nondimensional frequency and wavenumber range. (Author).
Download or read book Low Wavenumber Levels of Turbulent Boundary Layer Wall Pressure Fluctuations in Zero and Adverse Gradients written by Mark Jay Moeller and published by . This book was released on 1978 with total page 85 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Sensitivity to Mean Flow Parameters of the Low Wavenumber Content of the Wall Pressure Under a Turbulent Boundary Layer written by J. E Cole (III.) and published by . This book was released on 1985 with total page 45 pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this study is to examine the sensitivity of the low wavenumber portion of the wall pressure field under a turbulent boundary layer to both flow and wall conditions. The analytical procedure makes use of a method for calculating the broadband correlation function of the wall pressure field in which the specific flow characteristics enter through profiles of the mean velocity shear and turbulence intensity across the boundary layer. The basic assumption used to extend the results of this procedure to narrowband frequency characteristics is that there is a range of large spatial separations in which Strouhal scaling is not important. Several specific boundary layers are considered including flows on smooth and rough walls and in zero, favorable, and adverse pressure gradients. Results are presented for the point pressure, the spatial correlation function, and the low wavenumber spectral level. Keywords: GHR(General Hydromechanics Research) program; Wall pressure fluctuations; Low Wavenumber.
Download or read book Low Wavenumber Levels of a Turbulent Boundary Layer in Zero and Adverse Gradients written by Mark Jay Moeller and published by . This book was released on 1977 with total page 162 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Low Wavenumber Wall Pressure Fluctuations Due to Boundary Layer Transition written by and published by . This book was released on 2000 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Boundary layer transition is an important contributor to sensor flow-induced self noise. The pressure fluctuations caused by this spatially bounded and intermittent, phenomenon encompass a very wide range of spatial wave numbers and temporal frequencies. Here, we analyze the wavevector-frequency spectrum of the wall pressure fluctuations due to subsonic boundary-layer transition as it occurs on a flat plate under zero pressure gradient conditions. Based on previous measurements of the statistic of the boundary-layer intermittence it is found that transition induces higher low-streamwise wave number wall pressure level than does a fully-developed turbulent boundary layer (TBL) that might superficially exist at the same location and at the same Reynolds number. The transition zone spanwise wavenunmber pressure components are virtually unchanged from the TBL ease. The results suggest that transition may be more effective than the TBL in forcing structural excitation at low Mach numbers and it may have a more intense radiated noise contribution on a per unit area basis. This may help explain increases in measured sensor self noise when the sensors are placed near the transition zone.
Download or read book Predicting Turbulent Boundary Layer Wall Pressure Fluctuations in Adverse Pressure Gradients written by Frank J. Aldrich and published by . This book was released on 2005 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 138 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effects of Pressure Gradients on Turbulent Boundary layer Wall pressure Fluctuations written by Howard Hubert Schloemer and published by . This book was released on 1966 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The low-turbulence subsonic wind tunnel was significantly modified so that turbulent boundary-layer pressure fluctuation measurements could be made with adequate signal-to-noise ratio over a wide frequency range. Measurements were made in a mild adverse and a mild favorable pressure gradient with natural transition occurring in the boundary layer. To make certain that the facility was operating correctly and to establish a basis for comparison, the zero-pressure gradient case was investigated. For this case, the spectral density, magnitude of the normalized longitudinal and lateral cross-spectral density functions, and convection velocity as a function of longitudinal separation and frequency were in excellent agreement with other experimenters. When comparison is made to the zero-pressure gradient in the same non-dimensionalized frequency band and at similar non-dimensionalized longitudinal spacings, the convection velocity ratio is higher in the favorable and lower in the adverse pressure gradients, primarily due to the change in shape of the mean velocity profile. The effect of an adverse pressure gradient on the non-dimensionalized spectral density is to increase the low-frequency content without influencing the high-frequency portion appreciably, when compared to the zero-pressure gradient case. (Author).
Download or read book Turbulent Boundary Layers in Adverse Pressure Gradients written by Francis H. Clauser and published by . This book was released on 1953 with total page 146 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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.
Download or read book Comparison of the Wall Pressure Fluctuations in Artificially Generated Turbulent Spots Natural Transition and Turbulent Boundary Layers written by Thomas S. Mautner and published by . This book was released on 1988 with total page 9 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experiments have been conducted to measure the wall pressure fluctuations associated with artificially generated turbulent spots in a laminar boundary layer. The results show that both the rms wall pressure and the wall pressure spectra of turbulent spots are influenced by the local mean flow pressure gradient. The zero and favorable pressure gradient wall pressure data are in agreement with turbulent boundary layer results. However, the current spot data shows that, in the presence of an adverse pressure gradient, the spot's rms wall pressure is approximately 1.5-2.5 times larger than that found for the zero and favorable pressure gradient cases. These results are in general agreement with the adverse pressure gradient data of Huang and Hannan (1975). Additionally, the nearly constant magnitude of the spot's adverse pressure gradient wall pressure spectrum indicates a nearly even distributions of energy with frequency. Keywords: Turbulent boundary layer, Laminar boundary layer, Wall pressure fluctuations.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1995 with total page 704 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Technical Abstract Bulletin written by and published by . This book was released on with total page 1048 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Method for Predicting Compressible Turbulent Boundary Layers in Adverse Pressure Gradients written by Shimer Zane Pinckney and published by . This book was released on 1971 with total page 68 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Oscillatory Turbulent Boundary Layer in an Adverse Pressure Gradient written by Kyriacos Agamemnon Pericleous and published by . This book was released on 1983 with total page 486 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Effect of Pressure Gradients on Plate Response and Radiation in a Supersonic Turbulent Boundary Layer written by and published by . This book was released on 1997 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Adverse Pressure Gradient and Separating Turbulent Boundary layer Flows written by Andrew D. Cutler and published by . This book was released on 1984 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt:
