Changes between Version 11 and Version 12 of gallery/movies/forest

Timestamp:

Feb 20, 2014 11:17:57 AM (11 years ago)

Author:

kanani

Comment:

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gallery/movies/forest

@@ -83 +83 @@
 '''Responsible:''' [[imuk/members/kanani|Farah Kanani]], [[imuk/members/maronga|Björn Maronga]]\\
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-'''Description:''' The second sequence visualizes the transport of a passive tracer, which was homogeneously released at the domain surface. The data is from the same simulation as in the first sequence, but a smaller selection of the domain is shown and stretched in the vertical direction by a factor of 2. A certain range of lower tracer concentrations is represented by different shades of white, while a range of higher concentrations is drawn in shades of red. The colored surface represents near-surface values of the streamwise (edge-perpendicular) velocity component. Blue colors illustrate a flow from left to right and green colors mark the opposite flow direction. The arrows additionally illustrate direction and strength of the flow.
+'''Description:''' The second sequence visualizes the transport of a passive tracer, which was homogeneously released at the domain surface. The data is from the same simulation as in the first sequence, but a smaller selection of the domain is shown and stretched in the vertical direction by a factor of 6. A certain range of lower tracer concentrations is represented by different shades of white, while a range of higher concentrations is drawn in shades of red. The colored surface represents near-surface values of the streamwise (edge-perpendicular) velocity component. Blue colors illustrate a flow from left to right and green colors mark the opposite flow direction. The arrows additionally illustrate direction and strength of the flow.
 
 A region of tracer accumulation can be detected inside the forest, at a certain distance from the forest edge. This localized accumulation can be attributed to the horizontal convergence of the flow, resulting from the flow deceleration inside the forest. A reversed flow is even visible in this area, which enhances the convergence effect. Such a flow reversion sets up in dense forests, where the strong streamwise flow deceleration leads to a strong upward mass transport and hence creates a low pressure zone inside the forest. This in turn forces the flow to recirculate in order to compensate the mass loss. Looking at the tracer concentration reveals that the tracer distribution is fairly variable downstream of a forest edge, same as the tracer transport between forest and atmosphere. This adds high complexity to the interpretation of concentration and flux measurements near forest edges.\\