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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

An experimental investigation of flapping wing aerodynamics in micro air vehicles

Bradshaw, Christopher John 06 1900 (has links)
Approved for public release; distribution is unlimited. / Flapping-wing propulsion was studied experimentally through Laser Doppler Velocimetry. Measurements were both time-averaged and unsteady, and were conducted on a Micro-Air Vehicle (MAV) model developed at NPS by Professors Max Platzer and Kevin Jones. The objective of this work was to further understanding of the aerodynamics of flapping-wing propulsion. In specific, this study examined separation control on the leading fixed wing due to entrainment by the trailing flapping wings. Further, a study of wake topology examined differences between the optimal and off-optimal cases. Experimental studies took place in the NPS 5' x 5' low speed wind tunnel. The model was supported on a test stand and LDV measurements of the flow field were taken. Studies were made at varying freestream velocities, angles of attack, and flapping frequencies. The test stand was instrumented with force balances to show forces in both the streamwise and vertical directions. / Ensign, United States Naval Reserve
42

Rapid distortion theory for rotor inflows

Unknown Date (has links)
For aerospace and naval applications where low radiated noise levels are a requirement, rotor noise generated by inflow turbulence is of great interest. Inflow turbulence is stretched and distorted as it is ingested into a thrusting rotor which can have a significant impact on the noise source levels. This thesis studies the distortion of subsonic, high Reynolds number turbulent flow, with viscous effects ignored, that occur when a rotor is embedded in a turbulent boundary layer. The analysis is based on Rapid Distortion Theory (RDT), which describes the linear evolution of turbulent eddies as they are stretched by a mean flow distortion. Providing that the gust does not distort the mean flow streamlines the solution for a mean flow with shear is found to be the same as the solution for a mean potential flow with the addition of a potential flow gust. By investigating the inflow distortion of small-scale turbulence for various simple flows and rotor inflows with weak shear, it is shown that RDT can be applied to incompressible shear flows to determine the flow distortion. It is also shown that RDT can be applied to more complex flows modeled by the Reynolds Averaged Navier Stokes (RANS) equations. / Includes bibliography. / Thesis (M.S.)--Florida Atlantic University, 2013.
43

Evaluation of motion compensated ADV measurements for quantifying velocity fluctuations

Unknown Date (has links)
This study assesses the viability of using a towfish mounted ADV for quantifying water velocity fluctuations in the Florida Current relevant to ocean current turbine performance. For this study a motion compensated ADV is operated in a test flume. Water velocity fluctuations are generated by a 1.3 cm pipe suspended in front of the ADV at relative current speeds of 0.9 m/s and 0.15 m/s, giving Reynolds numbers on the order of 1000. ADV pitching motion of +/- 2.5 [degree] at 0.3 Hz and a heave motion of 0.3 m amplitude at 0.2 Hz are utilized to evaluate the motion compensation approach. The results show correction for motion provides up to an order of magnitude reduction in turbulent kinetic energy at frequencies of motion while the IMU is found to generate 2% error at 1/30 Hz and 9% error at 1/60 Hz in turbulence intensity. / by James William Lovenbury. / Thesis (M.S.C.S.)--Florida Atlantic University, 2013. / Includes bibliography. / Mode of access: World Wide Web. / System requirements: Adobe Reader.
44

Hydrodynamic drag of three-dimensional bodies by means of a Laser Doppler wake survey.

Knobel, John Richard January 1978 (has links)
Thesis. 1978. M.S.--Massachusetts Institute of Technology. Dept. of Ocean Engineering. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Bibliography: leaf 51. / M.S.
45

The prediction of fully-developed friction factors and Nusselt Numbers for randomly rough surfaces

Manning, Spencer Haynes. January 2005 (has links)
Thesis (M.S.) -- Mississippi State University. Department of Mechanical Engineering. / Title from title screen. Includes bibliographical references.
46

An investigation of interfacial instability during air entrainment

Veverka, Peter John 01 January 1995 (has links)
No description available.
47

Development of a volumetric 3D particle tracking velocimetry system and its application to mixing in a stirred tank

Cheng, Ye, January 2009 (has links)
Thesis (M.S.)--Rutgers University, 2009. / "Graduate Program in Mechanical and Aerospace Engineering." Includes bibliographical references (p. 116-118).
48

Schwingdrahtviskosimeter mit integriertem Ein-Senkkörper-Dichtemessverfahren für Untersuchungen an Gasen in grösseren Temperatur- und Druckbereichen /

Seibt, Daniel. January 1900 (has links)
Originally presented as the author's thesis--Universität Rostock, 2007. / Includes bibliographical references.
49

Stratified flow and turbulence over an abrupt sill /

Klymak, Jody Michael. January 2001 (has links)
Thesis (Ph. D.)--University of Washington, 2001. / Vita. Includes bibliographical references (p. 147-153).
50

A computational fluid dynamic study of blood flow through stenosed arteries / by Keng Cheng Ang.

Ang, Keng Cheng January 1996 (has links)
Errata has been inserted inside back pages. / Bibliography: leaves 180-186. / viii, 186 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Effects of stenoses on characteristics such as pressure drops, flow velocities and shearing stresses on the arterial walls are examined and their significance on the progression of arterial diseases is discussed. / Thesis (Ph.D.)--University of Adelaide, Dept. of Applied Mathematics, 1996

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