A Scanning Laser Velocimeter for Turbulence Research
A Scanning Laser Velocimeter for Turbulence Research

Author: National Aeronautics and Space Administration (NASA)

Publisher: Createspace Independent Publishing Platform

Published: 2018-08-20

Total Pages: 32

ISBN-13: 9781725628250

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Turbulent and unsteady separated flows occur on most practical flight vehicles, but are not yet sufficiently understood for designs to provide safe margins of performance without recourse to extensive experiment and computation. In date, reliable experimental data for even basic flows is severely limited and does not yet provide a satisfactory data base with which to assess current design and calculation methods. Although the laser velocimeter (LV) has become a proven, nonintrusive instrument for the measurement of local mean velocities and turbulence properties, measurements have been of a mean, statistical nature derived from averages accumulated independently at different positions in the flow. Thus, the measurements do not give an instantaneous dynamic, picture of the flow-field structures. Accordingly, a new technique for rapid LV scans of turbulent flow fields was proposed. The potential of this new instrument for fundamental fluid mechanical measurements of turbulent flows has been demonstrated. The results clearly show that significant unsteady flow features are hidden by conventional measurements and that the scanning laser velocimeter should prove an invauable tool in future studies of the structure of turbulent flows. Duen, F. K. Unspecified Center NASA-CR-172493, NAS 1.26:172493 NAS1-17572; RTOP 324-01-00-01...

Advances in Fluid Mechanics Measurements
Advances in Fluid Mechanics Measurements

Author: MOHAMED GAD-EL-HAK

Publisher: Springer Science & Business Media

Published: 2013-03-08

Total Pages: 611

ISBN-13: 3642837875

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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.

Perspectives in Turbulence Studies
Perspectives in Turbulence Studies

Author: Hans U. Meier

Publisher: Springer Science & Business Media

Published: 2012-12-06

Total Pages: 512

ISBN-13: 3642829945

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The present volume entitled "Perspectives in Turbulence Stud ies" is dedicated to Dr. Ing. E. h. Julius C. Rotta in honour of his 75th birthday. J. C. Rotta, born on January 1, 1912, started his outstanding career in an unusual way, namely in a drawing office (1928 - 1931). At the same time he - as a purely self taught perso- took a correspondence course in airplane construction. From 1934 to 1945 he worked in the aircraft industry on different subjects in the fields of flight mechanics, structures, air craft design, and aerodynamics. In 1945 he moved to Gottingen and worked from that time at the Aerodynamische Versuchsanstalt (AVA, now DFVLR) and the Max-Planck-Institut fur Stromungsforschung (1947-1958), interrupted only by a stay in the U. S. at the Glenn L. Martin Company (1954 - 1955) and a visiting professorship at the Laval University in Quebec, Canada (1956). Already during his activities in industry, Dr. Rotta discovered his special liking for aerodynamics. In Gottingen, he was attracted by Ludwig Prandtl's discussions about problems associated with turbulence and in particular his new contribution to fully developed turbulence, published in 1945. At that time, W. Heisenberg and C. F. v. Weizacker pub lished their results on the energy spectra of isotropic turbu lence at large wave numbers. Since that time his main research interest in reasearch has been in turbulence problems.

Monthly Catalog of United States Government Publications
Monthly Catalog of United States Government Publications

Author: United States. Superintendent of Documents

Publisher:

Published: 1985

Total Pages:

ISBN-13:

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February issue includes Appendix entitled Directory of United States Government periodicals and subscription publications; September issue includes List of depository libraries; June and December issues include semiannual index