The anatomy of a laminar starting plume. The entire plume is shown on the left, while a magnified image of the head is shown on the right. is the height of the plume from the outlet to the top of the head, is the width of the head, and is the head length. The plume shown is from set D5 and was created using an injected flow rate of . In this image, , , and .
The vertical position of the plume head as a function of time for the D4 experimental runs at five injection flow rates. The solid lines show the linear best fit for plume heights above . The slopes of these lines are the constant ascent velocity of each plume.
The dependence of the plume Richardson number on the Reynolds number of the injected fluid flow in the outlet pipe. The solid curve is a power law fit to the data, which gives . The dashed red line indicates . The symbol shading indicates the plume head morphology; shaded symbols indicate confined heads, while open symbols denote dispersed heads.
The nearly self-similar evolution of a typical confined plume head. Each image is apart. The plume is from set D5 and the injection rate was . From the first to the last image in the sequence, increases from , and the size of the head increases from to .
Head width as a function of head length for the D4 set of experiments. All of the plume heads in this set were confined. The head scales and have been nondimensionalized as Reynolds numbers and , respectively.
A sequence of images of a dispersed plume head during the evolution of a D2 starting plume with . Each image is apart. From the first to the last image in the sequence, increases from . The dimensions of the plume head in a) are and .
Head width as a function of head length for the D1 set of experiments, nondimensionalized as Reynolds numbers. With the exception of the plume with the lowest value of , all these plumes are dispersed. For all dispersed plumes, the head length grows faster than the width as the lobe becomes unstable.
An image of the axisymmetric hammer-shaped structure (indicated by the arrows) that results from the onset of a divergent flow structure beneath the underbelly of the head. This structure is not observed in confined heads. The head is from a D3 plume with injection rate . The dimensions of the plume are , , and .
Fluid properties of the various injected (subscript ) and ambient (subscript ) glycerol-water mixtures. Densities were measured with a densitometer at the same temperature at which a set of experimental runs were performed. The viscosities were interpolated from data given in Ref. 28.
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