Simulation of fluctuation effect on dendrite growth by phase field method

The dendrite growth process was simulated with the phase field model coupling with the fluctuation. The effect of fluctuation intensity on the dendrite morphology and that of the thermal fluctuation together with the phase field fluctuation on the forming of side branches were investigated. The results indicate that with the decrease of thermal fluctuation amplitude, the furcation of dendrite tip also decreases, transverse dendrites become stronger, longitudinal dendrites become degenerated, Doublon structure disappears, and a quite symmetrical dendrite structure appears finally. Thermal fluctuation can result in the unsteadiness of dendrites side branches, and it is also the main reason for forming side branches. The phase field fluctuation has a little contribution to the side branches, and it is usually ignored in calculation. When the thermal fluctuation amplitude (Fu) is appropriate, the thermal noise can result in the side branches, but cannot change the steady behavior of the dendrites tip.