fig2

Figure 2. Snapshots of a single dendrite in the downward buoyancy ((A) g_y = -g₀/5, (B) g_y = -g₀/2 and (C) g_y = -g₀) and the upward buoyancy ((D) g_y = g₀/5, (E) g_y = g₀/2 and (F) g_y = g₀) at t′ = 3.92 × 10⁶ to 6.67 × 10⁶, where the grayscale indicates the solutal concentration field, the flow velocity is marked by the colored arrows.