Skip to main content
  • Home
  • About
  • Faculty Experts
  • For The Media
  • ’Cuse Conversations Podcast
  • Topics
    • Alumni
    • Events
    • Faculty
    • Students
    • All Topics
  • Contact
  • Submit
Campus & Community
  • All News
  • Arts & Culture
  • Business & Economy
  • Campus & Community
  • Health & Society
  • Media, Law & Policy
  • STEM
  • Veterans
  • |
  • Alumni
  • The Peel
  • Athletics
Sections
  • All News
  • Arts & Culture
  • Business & Economy
  • Campus & Community
  • Health & Society
  • Media, Law & Policy
  • STEM
  • Veterans
  • |
  • Alumni
  • The Peel
  • Athletics
  • Home
  • About
  • Faculty Experts
  • For The Media
  • ’Cuse Conversations Podcast
  • Topics
    • Alumni
    • Events
    • Faculty
    • Students
    • All Topics
  • Contact
  • Submit
Campus & Community

‘Unsteady Vortex Formation of Low-Aspects-Ratio, Bio-Inspired Propulsors’

Wednesday, October 31, 2012, By News Staff
Share

Department of Mechanical and Aerospace Engineering Seminar

Friday, Nov. 2, 2:15-3:10 p.m., Watson Theatre, Watson Hall

Dr. Matthew Ringuette
Department of Mechanical & Aerospace Engineering
The State University of New York at Buffalo

In recent years substantial effort has been focused on understanding animal propulsion, e.g., that of fish, insects and birds. The application is small, highly maneuverable bio-inspired autonomous vehicles used for information gathering. The Reynolds number (Re) range is 102–104, and this coupled with low aspect ratio (AR) propulsors at high angles of attack creates flows dominated by separation and unsteady, 3-D vortex formation. More research is needed to understand the time-varying flow structure and its relationship to the forces. The focus of this talk is the characterization of these vortex flows using experiments with very simplified models and motions, which nonetheless produce highly complex flow structures and provide substantial insight. Two cases are considered, a rigid trapezoidal fin executing a rotational
starting motion, and rigid flat-plate wings rotating from rest; the latter is a simplified hovering half-stroke. The diagnostics are dye visualization, particle image velocimetry (PIV) and force measurements.

The fin generates a symmetrical ring-like vortex dominated by the tip vortex (TV), and substantial root-to-tip velocity. For large rotational amplitudes, the vortex sheds and a secondary one is generated while the plate is still moving, indicating saturation of the first. For different velocity programs, the TV circulation exhibits saturation as plateaus. Its behavior is complex due to an interaction with the root-to-tip flow, so a range of saturation times is defined. The lower bound indicates the initial TV pinch-off, and is reasonably predicted by a simple scaling.

The rotating-wing experiments focus on AR effects. Rectangular wings of AR = 2 and 4 with a fixed angle of attack of 45° are tested in a glycerin-water mixture, with a matched Retip = 5,000. The time-varying, 3-component volumetric velocity field is reconstructed using phase-locked, phase-averaged stereoscopic PIV in multiple chordwise planes. For both ARs the flow is initially a vortex loop consisting of a leading-edge vortex (LEV), the TV and the trailing-edge vortex. The AR = 2 case has greater spanwise velocity and a more helical LEV. After about 20° of rotation, the outboard LEV for each AR lifts up and is arch-like. For AR = 4 this is progressive and followed by breakdown. The AR = 2 flow is more coherent, and the greater influence of the TV contributes to a stronger flux of LEV vorticity to the tip, which mitigates lift-off.
Inboard the LEV is “stable,” and for both ARs has similar spanwise velocity and vorticity flux distributions. The AR = 2 lift coefficient shows a higher growth after startup.

Contact Person: Kathy Datthyn-Madigan, kjdatthy@syr.edu

  • Author

News Staff

  • Recent
  • Men’s Soccer Team Gives Back to Syracuse Community for Season of Support
    Friday, June 2, 2023, By Kathleen Haley
  • June 30 Deadline Set for Fiscal 2023 Year End Business
    Wednesday, May 31, 2023, By News Staff
  • DPS Accepting Sign-Ups for R.A.D. Summer Session
    Wednesday, May 31, 2023, By Alex Haessig
  • Syracuse Stage Adds 2 Musicals to 50th Anniversary Season
    Wednesday, May 31, 2023, By Joanna Penalva
  • Supporting, Advocating for Trans Youth Will Help Them Thrive As Adults
    Friday, May 26, 2023, By Daryl Lovell

More In Campus & Community

Men’s Soccer Team Gives Back to Syracuse Community for Season of Support

After their hard-earned National Championship season, energized by an outpouring of support, the Syracuse men’s soccer team wanted to respond in gratitude back to the community. Team members Noah Singelmann ’22 and Julius Rauch ’24 started a program, Sincere Impact,…

Project Mend Builds Community Through Writing for Those Impacted by the Justice System

For many years, Patrick W. Berry never told anyone that his father had been incarcerated for much of his life, as had several other members of Berry’s extended family. In fact, he tried not to think much about it. But eventually,…

June 30 Deadline Set for Fiscal 2023 Year End Business

Cash Operations has set a deadline of 3:30 p.m. on Friday, June 30, to receive deposits at the Bowne Cash Operations office for credit in fiscal year 2023. Deposits should be made as early in the day as possible on…

DPS Accepting Sign-Ups for R.A.D. Summer Session

The Syracuse University Department of Public Safety (DPS) is currently accepting sign-ups for its R.A.D. summer session. R.A.D., which stands for Rape Aggression Defense, is a nationally known self-defense program. This women-only self-defense course is being offered exclusively to Syracuse…

Syracuse Stage Adds 2 Musicals to 50th Anniversary Season

Syracuse Stage announced two musicals that will complete the lineup for the organization’s 50th anniversary season. Audiences are immersed in the soulful music of Billie Holiday with Lady Day at Emerson’s Bar and Grill, Oct. 18 through Nov. 5. Closing…

Subscribe to SU Today

If you need help with your subscription, contact sunews@syr.edu.

Connect With Us

  • Twitter
  • Facebook
  • Instagram
  • Youtube
  • LinkedIn
Social Media Directory

For the Media

Find an Expert Follow @SyracuseUNews
  • Facebook
  • Instagram
  • Youtube
  • LinkedIn
  • @SyracuseU
  • @SyracuseUNews
  • @SUCampus
  • Social Media Directory
  • Accessibility
  • Privacy
  • Campus Status
  • Syracuse.edu
© 2023 Syracuse University News. All Rights Reserved.