Speaker: Dr. Orkan Matt Umurhan, Physics Department, Technion.
Place: Holcblat
Time: Wednesday, 12/May/2004, 14:00
Title: Hydrodynamic Activity in Keplerian Disks
Abstract
Recent investigations have reconsidered the possibility that purely hydrodynamical processes can lead to sustained behavior in rotationally supported flows like Keplerian disks. In this context we consider the possibility that, though a local analysis of Keplerian flows linearly predicts long term stability, a nonlinear "bypass" type of transition into a sustained dynamically active state may be operating under such circumstances and is brought about through transiently growing linear behavior. We show in two and three dimensional simulations of homogeneous shear flow that these transiently growing modes can trip a system into a dynamically sustained state. I shall discuss these results within the context of the currently accepted paradigm proposed to describe and explain turbulence within accretion disks.