Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 32
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Book Description
Measurement of the wave number-frequency spectrum o(kl, w) of turbulent wall pressure fluctuations requires a line array (wave number filter) of closely spaced sensors. However, the wide range of wave numbers of the wall pressure fluctuations that contribute to the spectrum imposes constraints on sensor size, spacing, and number. In this study, the Corcos model of the wall pressure field is used in conjunction with recent experimental measurements to determine design parameters expressed in terms of boundary layer length and time scales. For the case of turbulent boundary layers at moderate to high Reynolds numbers, the resulting wave number design requires micro fabrication technology. Boundary layer, Filter design, Line array, Micro fabrication, Pressure sensor turbulent wall pressure, Wall pressure field, Wave number-frequency spectrum.
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 692
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Book Description
Author: Promode R. Bandyopadhyay
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 104
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Book Description
Author: Bruce M. Abraham
Publisher:
ISBN:
Category :
Languages : en
Pages : 418
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Book Description
Author: Richard M. Lueptow
Publisher:
ISBN:
Category : Science
Languages : en
Pages : 140
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Book Description
Author:
Publisher:
ISBN:
Category : Naval research
Languages : en
Pages : 312
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Book Description
Author: Kyle F. Martini
Publisher:
ISBN:
Category :
Languages : en
Pages : 280
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Book Description
The agreement between low wavenumber measurements of the turbulent wall pressure spectrum by various investigators has not been too good. Different techniques have been used in different facilities and have yielded data in different nondimensional frequency and wavenumber ranges. The current measurement program has utilized the wavenumber filtering techniques used by three primary investigators, the Martin plate, the Jameson plate and the Farabee and Geib 6-element microphone array in the same facility. Also a 12-element collinear and stagger array and a lateral array were used. The agreement between the different techniques in the M.I.T. facility is generally good. In addition, the difference of results between facilities has been reduced by displaying the data in a non-dimensional form that does not include the effect of boundary layer thickness. However, there was still a significant scatter in the data for each technique. Scatter is believed to be due to variation of each filter's wavenumber response away from the main acceptance lobe where the filter is responding to the acoustic and convective contamination and also the variation of the contamination with flow speed.
Author: MOHAMED GAD-EL-HAK
Publisher: Springer Science & Business Media
ISBN: 3642837875
Category : Science
Languages : en
Pages : 611
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Book Description
One cannot overemphasize the importance of studying fluids in motion or at rest for a variety of scientific and engineering endeavors. Fluid mechanics as an art reaches back into antiquity, but its rational formulation is a relatively recent undertaking. Much of the physics of a particular flow situation can be understood by conducting appropriate experiments. Flow visualization techniques offer a useful tool to establish an overall picture of a flow field and to delineate broadly its salient features before embarking on more detailed quantitative measurements. Among the single-point measurements that are particularly difficult are those in separated flows, non-Newtonian fluids, rotating flows, and nuclear aerosols. Pressure, shear stress, vorticity, and heat transfer coefficient are also difficult quantities to measure, particularly for time-dependent flows. These and other special situations are among the topics covered in this volume. Each article emphasizes the development of a particular measuring technique. The topics covered were chosen because of their importance to the field, recent appeal, and potential for future development. The articles are comprehensive and coverage is pedagogical with a bias towards recent developments.
Author: Eric Manoha
Publisher:
ISBN:
Category :
Languages : en
Pages :
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Book Description
Author: Elena Ciappi
Publisher: Springer
ISBN: 3319767801
Category : Technology & Engineering
Languages : en
Pages : 365
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Book Description
This is the proceedings of the Second International Workshop on Flow Induced Noise and Vibration (FLINOVIA), which was held in Penn State, USA, in April 2016. The authors’ backgrounds represent a mix of academia, government, and industry, and several papers include applications to important problems for underwater vehicles, aerospace structures and commercial transportation. The book offers a valuable reference guide for all those working in the area of flow-induced vibration and noise. Flow induced vibration and noise (FIVN) remains a critical research topic. Even after over 50 years of intensive research, accurate and cost-effective FIVN simulation and measurement techniques remain elusive. This book gathers the latest research from some of the most prominent experts in the field. The book describes methods for characterizing wall pressure fluctuations, including subsonic and supersonic turbulent boundary layer flows over smooth and rough surfaces using computational methods like Large Eddy Simulation; for inferring wall pressure fluctuations using inverse techniques based on panel vibrations or holographic pressure sensor arrays; for calculating the resulting structural vibrations and radiated sound using traditional finite element methods, as well as advanced methods like Energy Finite Elements; for using scaling approaches to universally collapse flow-excited vibration and noise spectra; and for computing time histories of structural response, including alternating stresses.
