Experiments to measure the heat transfer characteristics for various cavities situated at a duct-wall were performed. Flow visualization, measurements of pressure and temperature distributions on the heated bottom surface of cavity were carried out. It was observed that the effects of main flow stream, reattachment of separated flow, and vortex flow in the cavity on heat transfer unexpectedly large. It was found that heat transfer did not always decrease monotonously with an increase of aspect (depth-width) ratio D/W, in the flow range of laminar to turbulent. Correlations between Num and Rew were made in laminar and turbulent heat transfer ranges.

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1We investigate the early-time coalescence of two co-flowing axisymmetric turbulent plumes and the later-time flow of the induced vortices in a rotating, homogeneous fluid using laboratory experiments. The experiments demonstrate the critical importance of the rotation period T f = 2π/f , where f is the Coriolis parameter of the background rotation. We find that if the plumes' sources are sufficiently "close" for the plumes to merge initially at an "early time" time t m < ∼ t r = 3T f /4, the experimentally observed merging height z me agrees well with the non-rotating theoretical, where α is the entrainment "constant" of the turbulent plumes, x 0 is the separation distance between the two plume sources, F 0 is the source buoyancy flux of each plume, and z r is the distance that the plume rises in the time t r before rotational effects become significant. Therefore, rotation does not affect the initial time to merger or the initial merger height of such "close" plumes.

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