0

Full Content is available to subscribers

Subscribe/Learn More  >

Separation Bubbles Under Steady and Periodic-Unsteady Main Flow Conditions

[+] Author Affiliations
Weiliang Lou, Jean Hourmouziadis

Berlin University of Technology, Berlin, Germany

Paper No. 2000-GT-0270, pp. V003T01A075; 12 pages
doi:10.1115/2000-GT-0270
From:
  • ASME Turbo Expo 2000: Power for Land, Sea, and Air
  • Volume 3: Heat Transfer; Electric Power; Industrial and Cogeneration
  • Munich, Germany, May 8–11, 2000
  • Conference Sponsors: International Gas Turbine Institute
  • ISBN: 978-0-7918-7856-9
  • Copyright © 2000 by ASME

abstract

Based on an experimental investigation carried out in a low speed test facility at the Berlin University of Technology, this paper describes the formation of separation bubbles under steady and periodic-unsteady main flow conditions. The aim of the investigation was to understand the mechanism of separation, transition and reattachment and the effect of main flow unsteadiness on it.

Separation bubbles for various main flow conditions were generated over a large flat plate, which experienced a similar pressure distribution to that on the suction surface of blades in turbomachines. The pressure distribution was generated by a contoured wall opposite the plate. Aimed at separating the effect of the velocity and the turbulence wake, this paper considers only the influence of the velocity wake. To this effect, a rotating flap was mounted downstream of the test section to produce periodic oscillations of the main flow.

The overall flow field under steady main flow conditions was obtained by hot-wire measurements. Pressure taps were used to measure the pressure distribution over the plate. The Reynolds number effects were determined and compared to the measurement results in the literature. Results for periodic-unsteady separation bubbles are shown using different Strouhal numbers, oscillation amplitudes and Reynolds numbers. Ensemble averaged mean velocity profiles and the Ensemble averaged rms velocity profiles are used to demonstrate the development of the periodic boundary layer. Time-space diagrams are plotted to show the development of the periodic-unsteady boundary layers. The characteristic instability frequencies in the free shear layer are identified. The impact of the major parameters, Strouhal number and amplitude, on the bubble formation are discussed.

Copyright © 2000 by ASME

Figures

Tables

Interactive Graphics

Video

Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature

Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal

NOTE:
Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In