Alumni

Visiting Graduate Student from The Hong Kong Polytechnic University

akiyh@mit.edu

My research focuses on the initiation and evolution of large-scale coherent structures in finite vegetation canopy. Previous studies have shown that large-scale coherent structures can be observed along the patch lateral interface and the patch wake. Different kinds of large-scale coherent structures can be triggered at the same time and perform interaction with each other, further complicate the flow and turbulence structures. I will further investigate the impact of the large-scale coherent structures on the sediment transport.

Visiting Postdoc from University of Twente, Netherlands

thomasvv@mit.edu

Salt marshes are vegetated coastal wetlands with benefits for coastal protection, biodiversity, and carbon sequestration. Their complex interaction between currents, waves, fine sediments, and vegetation creates a dynamic shoreline that is resilient or erosive. Resilient salt marshes have sufficient sediment deposition to withstand erosion and may even expand, whereas erosive salt marshes are shrinking and provide fewer ecosystem services. My goal is to understand how salt marsh vegetation affects sediment deposition using experiments in the Nepf Lab wave-current flume. Vegetation can reduce current and wave velocities, which may enhance deposition. However, the interaction between currents, waves and vegetation also generates turbulence, which contributes to sediment resuspension. My experiments will define different regimes for sediment deposition under conditions with combined waves and currents. The results will provide insight on sediment deposition patterns on salt marshes, and, consequently, salt marsh resilience.

Graduate Student

jvbrice@mit.edu

My research is concerned with the design and implementation of nature-based coastal adaptation in urban settings. Despite increased interest in the incorporation of natural ecosystems in coastal engineering projects, there are still many gaps in our understanding of how these ecosystems perform hydrodynamically under extreme weather conditions and future climate scenarios. Using a combination of physical and numerical experiments, I will investigate wave attenuation and resilience of hybrid coastal defense strategies under various flow conditions, particularly the ability of oyster beds to reduce wave-driven flooding and overtopping during storms. I will then use a coastal-scale hydrodynamic model to explore implementation in an urban study area, with the goal of providing coastal communities with the tools to design physically and ecologically resilient waterfronts. Watch me on the “Ask MIT” Podcast.

Visiting Graduate Student from Dalian University of Technology
zhaocy(at)mit.edu

My research focuses on sediment transport in a submerged flexible meadow influenced by waves and current. Previous studies have shown that the near bed turbulence is the main trigger for sediment resuspension. In my study, I will measure vertical profiles of velocity and sediment concentration under different hydrodynamics conditions and uses these measurement to predict the threshold level of turbulence for sediment resuspension and deposition. Moreover, I will also consider how submerged flexible vegetation influences the formation of ripples in wave and current flow.

Undergraduate Student

slassar (at) mit.edu

When water with excess sediment flows through gravel streams it can clog the small spaces in between the gravel, known as interstitial spaces. These interstitial spaces are important for young fish, such as trout and salmon. I will work on a project modeling how sediment clogs up gravel streams, and investigate how adding obstacles (like logs, rocks, etc.) to these streams affects clogging. The turbulence created by adding these obstructions create can alleviate clogging, so this project aims to quantify if and how much clogging is prevented.

Assistant Professor National University of Singapore

garylei (at) mit.edu

Personal Website

Aquatic vegetation damps waves and currents, protecting shorelines from erosion. My research combines physical and numerical experiments to develop models that predict the impact of vegetation on wave damping, turbulence generation, and sediment fate. Read more about my work here.

Now PhD student at Penn State

autumnd (at) mit.edu

Coastal environments, such as mangrove forests, provide an unparalleled amount of ecosystem services, from water purification and flood prevention to the mitigation of climate change. In the Nepf Lab, I will investigate the critical conditions for erosion and deposition within black mangrove’s pneumatophores, which are also known as pencil roots because of their vertical and pencil-like shape. Pencil roots have an influence on sediment transport. They can both generate turbulence that can promote erosion and slow the currents near the bed that can promote deposition. If we know these critical conditions, then we can better understand the sediment fate and transport as well as how much carbon is stored in mangrove forests.

To determine these critical conditions, I am combining field work conducted in Port Fourchon, LA with laboratory methods. I will then use my observational field data and laboratory results to construct sub-grid scale models for erosion and deposition, which will be incorporated into a coastal-scale model to explore the role of channels in optimizing sediment retention within mangrove forests. 

Assistant Professor, Shenzhen University

Many natural plants are composed of leaves and stem, both of which are flexible and reconfigure (bend) in response to current and waves. The motion of plant elements impacts the plant drag, which in turn, modifies the flow structure and turbulent intensity, decreases in-canopy flow velocity, and dissipates wave energy. My research uses experiments with live and model plants, numerical simulation, and field investigation to understand the interaction of flexible plants with current and waves and to build physical-based simple predictive models for plant drag, flow structure, and wave dissipation.

MEng Student

rovi@mit.edu

Historically, logjams have been removed from rivers due to concerns of flooding, erosion, and destruction of property. However, new research has demonstrated that logjams have beneficial properties including generating pools that protect salmoniod spawing, propagule retention sites, and increasing biodiversity. For these reasons, engineered logjams are being introduced into rivers across the Northwest of the United States. To better identify the key components that enable logjams to create suitable habitat for salmonid fish, I am conducting physical experiments with model logjams. These experiments vary the dimensions and solid volume fraction of the log jam, and measure the velocity and turbulence in the wake. After characterizing the dimensional effects of the logjams, suggestions on which type of logjam is most suitable given what is known about fish preference are made.