The sink flow, taking place when water is drained from a tank through a small hole, is a well-known phenomenon.
Nevertheless the generation of swirl velocity has not been explained adequately.
Many factors act together in the swirl formation as small asymmetries in the flow vibration and effect of the Coriolis force due to the Earth’s rotation. This latter effect is negligible for small diameter tank.
The aim of the present project is to investigate on the appearance of the swirl accordingly to a global instability phenomenon in the case of symmetric container and neglecting Coriolis force.
The project is divided in two main steps:
1) Base-flow calculation through axisymmetric DNS
2) Global linear stability analysis on the base-flow
To this end, FreeFem++ finite element solver will be used.
Advisor: Francesco Viola