表面温度が周期的変化する系の凍結・融解に関する解析(永久凍土地帯における熱的挙動)(熱工学, 内燃機関, 動力など)

The study presents a numerical analysis on the thermal behavior of frozen-melting boundaries produced in the permafrost area subjected to the periodic changes of surface temperature. The simplified analytical model is introduced to postulate a single component, instead of water-contented soil, for taking a higher priority to reveal the thermal structure in the underground and the heat transfer mechanism across the surface as well as the frozen-melting boundaries. The analytical results show the temperature profiles produced in the active layer to disclose the drastic changes for the coalescence of two adjacent frozen solid layers separated by the liquid and vice versa. The temperatures in the deep underground, maintained almost constant similar to the Stokes 2nd problem, are found to be dereased to rather lower compared with the mean temperature at the surface. The futher detailed discussions are executed on the heat transfer mechanism on the transient phenomena in the mid- and long-term perspectives of environmental effects and climate changes.