SYMMETRY-BREAKING FLOW TRANSITIONS AND OSCILLATORY FLOWS IN A 2D DIRECTIONAL SOLIDIFICATION MODEL

Time-dependent flow in a 2-D model of crystal growth by the Bridgman-S tockbarger method is examined using a pseudo-spectral Chebyshev colloc ation method. The governing Navier-Stokes-Boussinesq equations yield s olutions which exhibit a symmetry-breaking flow transition, oscillator y behaviour with period doubling and quasi-periodic transitions at hig her values of Ra. The results are discussed frome a fluid dynamic view point and broader implications for process models are also addressed.