安定成層内の熱気流に発生するサーマル気筒による熱流動 : 第1報,温度特性(熱工学,内燃機関,動力など)

抄録

By analyzing numerically a buoyant flow in stably stratified air in an enclosure, a thermal cylinder was found and the cross-over phenomenon (CO) was elucidated as follows: A plume occurred time-averagedly from a line heat source and its height was suppressed by stratification. To transport heat upwards from the plume front, an isothermal line was divided near the front and a thermal cylinder was generated. The time-averaged temperature decreased upwards in the plume, and the temperature at the front became lower than that in environment. Thus, the time-averaged cross-over occurred. In the region where thermal cylinders were rising intermittently above the front, the convective heat was transported by thermal cylinders and the conductive heat were transported from above and both side. As a result, the time-averaged temperature of the buoyant flow increased upwards and approached the environment temperature.