Marco Ghisalberti
<marcog@mit.edu>
Marco is conducting an experimental study into the effects of submerged, flexible vegetation on aquatic flows. Using the laboratory flume, the structure of unidirectional flows with submerged vegetation was shown to be similar to that of a mixing layer. His current research involves: (i) looking at the effect of waves on this mixing-layer analogy, and (ii) the characterization, through dye studies, of mass transport in these flows.
Molly Palmer
<mollyp@mit.edu>
Molly is working on lab experiments to simulate particle capture by vegetation in wetlands. Understanding how particles encounter and are trapped by plants is vital to understanding the relationship between wetland vegetation and water quality. The picture shown is of a cylinder (representing a plant stem) covered with small plastic particles (representing real aquatic particles).
Yukie Tanino
<ytanino@MIT.EDU>
Yukie is studying the trapping and release of fluid in the wakes of emergent plant stems using rigid cylinders as an experimental model for stems. She is currently designing an experiment that will examine how changing the spacing between the cylinders affects this transport process. The objective of this project is to determine key parameters that will be used to predict the magnitude of longitudinal dispersion in different aquatic canopies.
Brian White
<blw@mit.edu>
Image: Spreading of dye in a random cylinder array, a model for an emergent canopy. Flow is from the top to the bottom. Reynolds number based on cylinder diameter is 20.
Brian's research describes the mixing and dispersion of passive species within plant canopies using fluid physics, statistical analysis, and experimental measurements. The effect of stem-scale heterogeneity in the mean velocity field and temporal heterogeneity associated with stem-wake behavior is of particular interest. Previous work has focused on transport deep wtihin an emergent canopy. His next project will examine the mixing in exchange zones between canopies and open channels, which are characterized by large coherent vortices similar to those observed in free shear layers.
Anne Lightbody
<lightbod@MIT.EDU>
Anne is planning a field study in the Plum Island Estuary in Rowley, Massachusetts, examining the contribution of emergent marsh grass (Spartina alterniflora) stems to mixing within aquatic flows. The study will involve the release of dye and the measurement of its longitudinal dispersion over a short stretch of vegetation with the goal of testing predictions generated by a theoretical model developed by Brian White.
