BUOYANT FLOW CHARACTERISTICS WITH THERMAL CYLINDERS IN STABLY STRATIFIED AIR

ABSTRACT A flow induced by thermal cylinders at neutral (st = 0) or stable (0 < st) stratification, where st is the stratification degree, is analyzed numerically. As a result, a new kind of flow resulting from thermal cylinders is discovered, and agrees well with the previous experimental result of flow visualization as follows: At 0 ≤ st, the thermal cylinder flow (TCF) is defined as the flow due to a thermal cylinder, and is generated intermittently. A TCF rises and develops to a small roof-shape flow, which separates to the right and left directions near the thermal flow front. Then, at st = 0 and a small st, one edge of a layer is fixed near the midplane, and another edge of a layer moves outward. Thus a nonslip-type layer is formed. Furthermore, because many thermal cylinders arrive intermittently at the front, many layers of nonslip type are formed. On the other hand, at a large st, all the layers slip off the midplane, and move slowly outward. As a result, many layers of slip type are formed.