The Nepf Lab, November 2015

Front Row: Heidi Nepf, Amir M. Razmi, Elizabeth Follett, Judy Yang,
Zhenghong "Rainbow" Hu

Back Row: Maria Maza, Hayoon Chung, Gary Lei, Katherine Adler, Chao Yan
The Nepf Lab, February 2016

Front Row: Hayoon Chang, Judy Yang, Milani Chatterji-Len, Zhenghong "Rainbow" Hu, Elizabeth Follett

Back Row: Diogo Ramos, Maria Maza, Katherine Adler, Heidi Nepf, Gary Lei, Manoel Xavier


Heidi Nepf
Donald and Martha Harleman Professor
Civil and Environmental Engineering

Email: hmnepf (at) mit.edu

Heidi Nepf's Civil and Environmental Engineering webpage
Professor Nepf's teaching includes Physical Limnology and Transport Processes in the Environment.

Elizabeth Follett

Graduate Student (Email: efinn (at) mit.edu

By forecasting the spread of fungal spores, we can reduce the amount of fungicide applied each year to crops such as corn, wheat, and soybeans. My research focuses on developing an understanding of the processes governing spore escape from a crop canopy, so that we can refine existing estimates of the probability of spore escape. Using a rigid model crop canopy, I study theimpact of canopy scale vortices on particle transport using a combination of flow visualization techniques and measurements of deposition following an experimental particle release. I have also developed a simple random walk particle tracking model to explore particle escape across a wide range of canopy densities and ratios of spore settling velocity to canopy turbulence.

Qingjun "Judy" Yang
Graduate Student (Email: qjyang (at) mit.edu)


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.

Gary Lei
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.

Maria Maza
Postdoctoral Associate
(Email: mazame (at) mit.edu)

Numerical and experimental modeling of coastal protection provided by vegetation:
- Experimental study of waves and currents interaction with real vegetation.
- Advanced RANS three dimensional modeling and experimental analysis of waves interaction with rigid vegetation.
- New formulation for vegetation induced wave damping under waves and current condidtions.
- Wave interaction with vegetation patches.

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.


Chao Yan
Visiting Graduate Student
(Email: yanc (at) mit.edu)
The Department of Engineering Mechanics
Tsinghua University, Beijing, China

Vegetation is known to influence its surrounding terrestrial and aquatic environments, yet the influences have not been well understood. During my postgraduate study, I mainly focus on analyzing the interaction between vegetation and environment in terms of numerical simulation. Specifically, I am performing Large Eddy Simulations (LES) of turbulent flow over model plant canopies, with the aim of visualizing the underlying fundamental processes, such as turbulent transfer and mass transport. Through this kind of research, I intend to unearth the physical mechanisms determining how momentum and scalar are transported in regions with vegetation, thus advancing our knowledge of the vegetation-enviroment interaction.

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

Brenda Ellen Pepe
Administrative Assistant, Nepf Lab (pepebe@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.