Influence of natural convection on the melting of ice block surrounded by water on all sides

The ice block at initial temperature Tis = 0 °C is fixed at the center of a long, prismatic enclosure with isothermal vertical walls and insulated horizontal walls. The enclosure is completely filled with water at initial temperature Til = 0 °C. Six numerical simulations were performed by varying vertical wall temperatures from TW = 2 to 12 °C (range of Rayleigh number from 4.22 × 106 to 2.28 × 107). In the case of TW > 8 °C the ice melts faster from above and for TW < 8 °C from below. In the case of TW = 8 °C, two vortices are separated by nearly vertical 4 °C isotherm and the average Nusselt number remains constant during the convection dominated regime.