Instabilities in Natural-Convection Flows in Cavities

摘要

In the thesis, a study of instabilities occurring in a natural-convection flow isdescribed. Natural-convection flows arise from density differences in a fluid. These density differences, under the influence of the earth's gravity field, result in a buoyant force which causes the heavier fluid particles to descend and the lighter fluid particles to ascend and which thus drives the resulting flow. The adjective natural is used to distinguish these flows from forced-convection flows which are driven by pressure differences. The density differences occurring in natural-convection flows may have their origin in a number of different physical phenomena; they may result from temperature differences, from differences in the concentration of chemical species in the fluid and from the presence of multiple phases in the fluid. In the present study, however, only flows in which the density differences are caused by temperature differences are considered.