FLOW INSTABILITIES AND REVERSALS IN NON-UNIFORMLY THERMOCAPILLARY DRIVEN MELT POOL etc15 Tracking Number 486Presentation: Session: Instability and Transition 7 Room: Room A Session start: 10:30 Fri 28 Aug 2015 Anton Kidess A.Kidess@tudelft.nl Affifliation: Delft University of Technology Sasa Kenjeres S.Kenjeres@tudelft.nl Affifliation: Delft University of Technology Chris R. Kleijn C.R.Kleijn@tudelft.nl Affifliation: Delft University of Technology Topics: - Instability and transition, - Wall bounded flows, - Large eddy simulation and related techniques, - Thermally driven turbulence Abstract: With transient LES and DNS simulations, we investigate flow in melt pools driven by thermocapillary forces. The developing pool is at first axisymmetric as are the boundary conditions, but flow instabilities arise that lead to 3D oscillatory flow patterns. At higher laser powers a sign-change in the surface tension temperature coefficient occurs, resulting in a flow reversal in the pool and thus two counter-rotating vortices, which exhibit similar though more complex flow instabilities. |