Flow past a Flat Plate-Hemisphere Juncture
These images illustrate the interaction of a flat plate boundary layer
with a hemispherical protuberance.
The Reynolds number based upon hemisphere radius is Re=600, and the boundary
layer thickness is approximately equal to the radius. These results were
computed using 512 elements of order 16 (2.1 M points) on the 512-node
Intel Delta at Caltech.
This flow has also been extensively studied experimentally under similar
conditions by Acalar and Smith [ JFM }, 175 , 1987],
and for thicker boundary layers by Klebanoff, Cleveland, and Tidstrom
[ JFM }, 237 , 1992].
This work is part of the thesis work of Henry Tufo
and is supported by NSF under Grant ASC-9405403
and by AFOSR Grant F49620-95-1-0074.
Computer time was provided on the Intel Delta and Paragon at Caltech
by the Center for Research on Parallel Computation
under NSF Cooperative agreement CCR-8809615.
Centerplane contours of spanwise vorticity reveal hairpin
vortices in the hemisphere wake.
Contours of spanwise vorticity (centerplane) and
streamwise vorticity (foreground) illustrate the
structure of the hairpin vortices.
Streamlines show the steady horseshoe vortex
formed on the windward side of the hemisphere.
In these two figures
the downstream hairpin vortices are identified
using the definition of a vortex given by Jeong and Hussain
[ JFM }, 285 , 1995]
(as iso-surfaces of an
eigenvalue of a symmetric tensor derived from the velocity
Additional hairpin vortex information.
Other spectral element simulations.