FORMATION PROCESS OF THE TRAVELING-WAVE STATE WITH A DEFECT IN BINARY-FLUID CONVECTION

We give results of simulations on the transient evolution from conduct ion to an extended traveling wave (ETW) state containing a sink defect slightly above the onset of the subcritical instability for a binary fluid mixture with the separation ratio psi = -0.47 confined in a rect angular cell of aspect ratio Gamma = 46. The simulation was performed using the two-dimensional full fluid equations of motion. We find that the system starting from a conduction state first experiences a linea r stage with independently counterpropagating wave (CPW) packets and t hen develops a modulated traveling wave (MTW) and a traveling wave (TW ) containing transient sink and source defects. It then ultimately evo lves into a TW with a stable sink defect similar to those observed in experiments. For our parameters, the system evolves into the nonlinear regime as the lateral concentration profile becomes a trapezoidal, st rongly non-harmonic shape in the localized regions. Comparisons with o ther calculations and experiments are presented.