**SMS scnews item created by Eduardo Altmann at Tue 22 Aug 2017 1647**

Type: Seminar

Distribution: World

Expiry: 19 Sep 2017

**Calendar1: 6 Sep 2017 1400-1500**

**CalLoc1: AGR Carslaw 829**

CalTitle1: Flow external to a rotating torus (or a sphere)

Auth: ega@como.maths.usyd.edu.au

### Applied Maths Seminar

# Flow external to a rotating torus (or a sphere)

### Calabretto

Dr. Sophie
Calabretto (Department of Mathematics,Macquarie University)

** Title:** Flow
external to a rotating torus (or a sphere)

** Abstract: ** The unsteady flow
generated due to the impulsive motion of a torus or sphere is a paradigm for the study
of many temporally developing boundary layers. The boundary layer is known to exhibit a
finite-time singularity at the equator. We present results of a study that focuses upon
the behaviour of the flow after the onset of this singularity. Our computational
results demonstrate that the singularity in the boundary layer manifests as the ejection
of a radial jet. This radial jet is preceded by a toroidal starting vortex pair, which
detaches and propagates away from the sphere. The radial jet subsequently develops an
absolute instability, which propagates upstream towards the sphere surface.

Applied Maths Seminars Webpage:
http://www.maths.usyd.edu.au/u/SemConf/Applied.html