Development of a fluids laboratory experience in dimensional analysis and similitude applied to vortex shedding from a cylinder in cross-flow

Matthew Anderson, Dylan Shiltz, Christopher Damm

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

A fluids laboratory experience that introduces students to dimensional analysis and similitude was designed and performed in a junior-level first course in fluid mechanics. After students are given an introduction to dimensional analysis, the technique is applied to the phenomenon of vortex shedding from a cylinder in cross-flow. With help from the instructor, lab groups use dimensional analysis to ascertain the relevant dimensionless pi terms associated with the phenomenon. After successfully determining that the pi terms are the Strouhal number and the Reynolds number, experiments are performed to elucidate the general functional relationship between the dimensionless groups. To conduct the experiments, a wind-tunnel apparatus is used in conjunction with a Pitot tube for measurements of free stream velocity and a platinum-plated tungsten hot-wire anemometer for rapid (up to 400 kHz) measurements of velocity fluctuations downstream of the cylinder. Utilizing an oscilloscope in parallel with a high-speed data acquisition system, students are able to determine the vortex shedding frequency by performing a spectral analysis (via Fourier transform) of the downstream velocity measurements at multiple free stream velocities and for multiple cylinder diameters (thus a varying Reynolds number). The students' experimental results were found to agree with relationships found in the technical literature, showing a constant Strouhal number of approximately 0.2 over a wide range of Reynolds numbers. This exercise not only gives students valuable experience in dimensional analysis and design of experiments, it also provides exposure to modern data acquisition and analysis methods.

Original languageEnglish (US)
Title of host publicationEducation and Globalization
PublisherAmerican Society of Mechanical Engineers (ASME)
ISBN (Print)9780791856277
DOIs
StatePublished - Jan 1 2013
Externally publishedYes
EventASME 2013 International Mechanical Engineering Congress and Exposition, IMECE 2013 - San Diego, CA, United States
Duration: Nov 15 2013Nov 21 2013

Publication series

NameASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE)
Volume5

Other

OtherASME 2013 International Mechanical Engineering Congress and Exposition, IMECE 2013
CountryUnited States
CitySan Diego, CA
Period11/15/1311/21/13

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