Naval Postgraduate School
Dudley Knox Library
NPS Dudley Knox Library
View Item 
  •   Calhoun Home
  • Theses and Dissertations
  • 1. Thesis and Dissertation Collection, all items
  • View Item
  •   Calhoun Home
  • Theses and Dissertations
  • 1. Thesis and Dissertation Collection, all items
  • View Item
  • How to search in Calhoun
  • My Accounts
  • Ask a Librarian
JavaScript is disabled for your browser. Some features of this site may not work without it.

Browse

All of CalhounCollectionsThis Collection

My Account

LoginRegister

Statistics

Most Popular ItemsStatistics by CountryMost Popular Authors

Effects of 1, 2, 3 and 4 Hz imposed bulk flow oscillations on transition in a straight channel with 40 to 1 aspect ratio

Thumbnail
Download
Icon90Jun_Koth.pdf (5.499Mb)
Download Record
Download to EndNote/RefMan (RIS)
Download to BibTex
Author
Koth, Howard Edwin
Date
1990-06
Advisor
Ligrani, Phillip M.
Subramanian, Chelakara S.
Metadata
Show full item record
Abstract
A channel with 40 to 1 aspect ratio and rectangular cross-section is used to study the effects of imposed oscillations on transition from laminar to turbulent flow. Oscillations are imposed using a single rotating vane located in the flow downstream of the test section. Flows with Reynolds numbers ranging from 1100 to 3580 and Strouhal numbers from 0.0211 to 0.2418 are studied. For all cases, time-averaged velocity profiles are unaffected by imposed oscillations. Imposed oscillations have a destabilizing effect on the flow near the edge of the Stokes layer. Turbulence intensity magnitudes with imposed oscillations show that transition to turbulence begins at lower Reynolds numbers and extends over a wider range of Reynolds numbers than when no imposed oscillations are present. In addition, higher levels of intermittency are present with imposed oscillations for Reynolds numbers 1900 to 2200 at yd=0.90. At Reynolds numbers from 1450 to 1800, frequency spectra evidence high intensity intermittent turbulent fluctuations, followed and preceded by quiescent flow, both with and without imposed oscillations. A center mode of secondary instability is evidenced by high values of normalized longitudinal turbulence intensity measured in the channel center when no oscillations are imposed on the flow. Imposed oscillations are found to suppress this center mode of secondary instability, as evidenced by reductions in longitudinal turbulence intensity values near the channel center.
Rights
This publication is a work of the U.S. Government as defined in Title 17, United States Code, Section 101. Copyright protection is not available for this work in the United States.
URI
http://hdl.handle.net/10945/27774
Collections
  • 1. Thesis and Dissertation Collection, all items

Related items

Showing items related by title, author, creator and subject.

  • Thumbnail

    Effects of 1 Hz imposed bulk flow unsteadiness on laminar/turbulent transition in a straight channel 

    Coumes, Thomas M. (Monterey, California. Naval Postgraduate School, 1989-12);
    Laminar/turbulent transition is studied in a straight channel with 1 Hz imposed bulk flow unsteadiness for Reynolds numbers of 1103 to 2715 and Strouhal numbers of 0.06045 to 0.02455. Channel aspect ratio is 40 to 1 with ...
  • Thumbnail

    Effects of 2 Hz imposed bulk flow unsteadiness on laminar/turbulent transition in a straight channel. 

    Greco, Francis J. (Monterey, California. Naval Postgraduate School, 1989);
    Laminar turbulent transition is studied in a straight channel with 2 Hz imposed bulk flow unsteadiness for Reynolds umbers of 1 100 to 3800 and Strouhal numbers of 0.121 to 0.035. Channel aspect ratio is 40 to 1 with 1.27 ...
  • Thumbnail

    Study of transition phenomena in a straight channel with 40 to 1 aspect ration with and without imposed pulsations Part two: Reynolds number surveys 

    Smith, Bradley Joseph (Monterey, California. Naval Postgraduate School, 1991-03);
    A channel with rectangular cross-section, 40 to 1 aspect ratio (height is0.0127 m) and 4.27 m test section length (336 channel lengths) is used to study the effects of imposed pulsations on laminar, transitional, and ...
NPS Dudley Knox LibraryDUDLEY KNOX LIBRARY
Feedback

411 Dyer Rd. Bldg. 339
Monterey, CA 93943
circdesk@nps.edu
(831) 656-2947
DSN 756-2947

    Federal Depository Library      


Start Your Research

Research Guides
Academic Writing
Ask a Librarian
Copyright at NPS
Graduate Writing Center
How to Cite
Library Liaisons
Research Tools
Thesis Processing Office

Find & Download

Databases List
Articles, Books & More
NPS Theses
NPS Faculty Publications: Calhoun
Journal Titles
Course Reserves

Use the Library

My Accounts
Request Article or Book
Borrow, Renew, Return
Tech Help
Remote Access
Workshops & Tours

For Faculty & Researchers
For International Students
For Alumni

Print, Copy, Scan, Fax
Rooms & Study Spaces
Floor Map
Computers & Software
Adapters, Lockers & More

Collections

NPS Archive: Calhoun
Restricted Resources
Special Collections & Archives
Federal Depository
Homeland Security Digital Library

About

Hours
Library Staff
About Us
Special Exhibits
Policies
Our Affiliates
Visit Us

NPS-Licensed Resources—Terms & Conditions
Copyright Notice

Naval Postgraduate School

Naval Postgraduate School
1 University Circle, Monterey, CA 93943
Driving Directions | Campus Map

This is an official U.S. Navy Website |  Please read our Privacy Policy Notice  |  FOIA |  Section 508 |  No FEAR Act |  Whistleblower Protection |  Copyright and Accessibility |  Contact Webmaster

Export search results

The export option will allow you to export the current search results of the entered query to a file. Different formats are available for download. To export the items, click on the button corresponding with the preferred download format.

A logged-in user can export up to 15000 items. If you're not logged in, you can export no more than 500 items.

To select a subset of the search results, click "Selective Export" button and make a selection of the items you want to export. The amount of items that can be exported at once is similarly restricted as the full export.

After making a selection, click one of the export format buttons. The amount of items that will be exported is indicated in the bubble next to export format.