My current research is focused on the sediment transport inside a vegetation patch. Vegetation is a basic component of most natural water environments and has been widely used in river restoration. Yet few practical models exist to predict the incipient motion and rate of sediment transport in a canopy. Using a LDV, a high-speed camera and a sediment-recirculating flume, I will be able to quantitatively connect the sediment motion with the flow characteristics inside vegetation canopies.
Graduate Student (Email: garylei (at) mit.edu)
My project aims to understand how the rate of nutrient flux to the plant changes with the motion and posture of individual blades. The impacts of neighboring blades on nutrient flux will also be examined. I will work with both meadow and model blades which are constructed from low-density polyethylene (LDPE). The LDPE blade can absorb chemicals injected in the flume water, to simulate the nutrient-uptake of sea grass and freshwater macrophytes. This project will extend existing models for drag /flux to individual blades in current, and also explore a predictive model for mass flux based on different flow conditions.
Amir M. Razmi
Postdoctoral Fellow (Email: arazmi (at) mit.edu)
Flow structure and transport processes are markedly complex in the presence of vegetation due to the complex interaction of the turbulent flow with flexible vegetations. The existing physical models are still failed to predict such interactions with the real vegetations due to its complex nature.
My ongoing research is to better understand the impact of real vegetations on canopy flows and study its associated turbulence and re-suspension processes. To do so, I deploy a combination of numerical simulations (LES), lab experiments, and analytical tool.
Applications of my research are in a wide range of environmental problems, including pollution and sediment dispersion surrounding aquatic vegetations, coastal protection against extreme climatic events, and aerosol transport above the terrestrial vegetations.
Zhenghong "Rainbow" Hu
Visiting Graduate Student (Email: zhhhu(at) mit.edu)
State Key Laboratory of Hydraulics and Mountain River Engineering
Sichuan University, Chengdu, China
I study the flow and deposition around a rigid, submerged vegetation patch with different submergence depth. Three-dimensional flow structure will be present for submerged vegetation, since shear layers will be formed in the both vertical and horizontal direction which is different from two=dimensional flow adjustment for emergent vegetation. The goal is to connect the enhanced and reduced deposition regions to the flow turbulent and mean velocities, so that we can explain the deposition in different submerged conditions. These observations can also describe the morphological feedbacks between flows, deposition with submerged patches.
Manoel Lucas Machado Xavier
International Visiting Student (Email: mavier (at) mit.edu or mavier89 (at) gmail.com)
My current research is focused on developing ways to quantify the time spent by scalars (pollutants, sediments, nutrients, etc.) in the root zone of floating treatment wetlands, as well as the amount of mass that is entering the wetland by using computational fluid dynamics and physical experiments. Both of these metrics are key to quantify how well a wetland is going to perform within a water body since the root zone is the main area where treatment is going to happen. The result of this work is going to be applied at two sites, one in Houston and one in Los Angeles where wetlands are going to be used for stormwater treatment.
Brenda Ellen Pepe Administrative Assistant, Nepf Lab (pepebe (at) mit.edu)
I am a proud Boston College alumnus, class of 1985 (WCAS) and 1989 (GA&S). I live on the South Shore and in my free time I enjoy gardening, reading, travel, and genealogy research.