Simulated large-scale circulation of turbulent Rayleigh-Benard convection in a vertical thin disk

These two movies show the large-scale circulation of turbulent Rayleigh-Benard convection at Pr = 0.17 (left) and Pr = 4.4 (right), respectively. Both movies are obtained by direct numerical simulation (DNS) at Ra = 5x109 in a vertical thin circular disk cell with an aspect ratio (thickness over diameter) of 0.1. The color code used shows a linear dimensionless temperature scale ranging from -0.5 to 0.5. Dark red shows the highest dimensionless temperature of 0.5 (bottom heating plate) and dark blue shows the lowest dimensionless temperature of -0.5 (top cooling plate).

Click the pictures to see the motion of large-scale circulation at low-Pr and high-Pr. The movie for Pr = 0.17 is played at 4.2 free-fall time per second and the movie for Pr = 4.4 is played at 4 free-fall time per second.