FLUID MECHANICS SEMINAR
Investigation of Turbulent Spot Transition Over Riblets
Jeff Chu
ASE/EM
In the relatively low Reynolds number regime (Rex=U∞x/ν≤105) , incompressible flow over a flat plate subjected to zero pressure gradient remains smooth and laminar. As Rex increases, the flow develops instabilities before transition to turbulence occurs. As the instabilities grow they trigger the formation of randomly distributed arrow-head shaped turbulent spots in the flow.
If one could delay the onset of laminar to turbulent transition, the benefits would be substantial since the viscous drag of a turbulent boundary layer can be four or more times greater than that of a laminar layer. One promising idea is to use passive surface textures such as streamwise riblets to reduce the spreading angle of turbulent spots.
Several physical and unphysical simulations were conducted to visualize how the turbulent spot spreads and identify the contributing factors with an eye toward developing surface textures to mitigate such spreading.
DATE: Thursday, November 19, 2009
TIME: 3:30 p.m.
LOCATION: WRW 113
Refreshments will be served.
For further information please contact
D. Goldstein (471-4187) |
