Investigation of the effect of a circular patch of vegetation on turbulence generation and sediment deposition using four case studies
Ortiz, Alejandra C.
MetadataShow full item record
This study describes the spatial distribution of sediment deposition in the wake of a circular patch of model vegetation and the effect of the patch on turbulence and mean flow. Two difference types pf vegetation were used along with two different stem densities totaling four different case studies. The spatial location of enhanced deposition correlated with the steady wake zone, which has length, L1. The steady wake zone only occurred downstream of the rigid emergent patches of vegetation and was not seen downstream of the flexible submerged patches of vegetation. The enhanced deposition occurred when both turbulence and mean velocity was below the upstream, initial values. The enhanced deposition occurred when the mean velocity was less than or equal to half of the initial velocity. For the four cases studied, theses parameters of low velocity and low turbulence were primarily met within the steady wake region immediately downstram of the two rigid emergent patches of vegetation. In all four cases, large coherent structures are created in the flow due to the patch. Lateral vortices are formed downstream of the patch in a von-Karman vortex street that meets at the center of the flow a distance, Lw, downstream of the patch. For the flexible submerged cases, streamlines reattach to the bed of the flume a distance, Lv, downstream of the patch. In addition, for the flexible submerged cases, a secondary circulation is generated with flow moving laterally away from the patch at the surface and toward the centerline of the patch at the bed.
Submitted in partial fulfillment of the requirements for the degree of Master of Science at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution June 2012
Showing items related by title, author, creator and subject.
Moberg, Emily A. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2016-09)Marine populations are increasingly subjected to changing conditions whether through harvest or through broad-scale habitat change. Historically, few models have accounted for such trends over time, and even fewer have ...
Ecology of chemical defenses of algae against the herbivorous snail, Littorina littorea, in the New England rocky intertidal community Geiselman, Joy Ann (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1980-02)In the New England rocky intertidal community, space is dominated by two perennial plant types, brown fucoid algae (Ascophyllum nodosum and several species of Fucus) in the mid zones and the red alga Chondrus crispus ...
Experimental and seismological constraints on the rheology, evolution, and alteration of the lithosphere at oceanic spreading centers deMartin, Brian J. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2007-02)Oceanic spreading centers are sites of magmatic, tectonic, and hydrothermal processes. In this thesis I present experimental and seismological constraints on the evolution of these complex regions of focused crustal ...