This proposal develops an accurate and efficient method for modeling the interaction of fluid with numerous flexible plant stems (modeled as bendable cylinders) at a wide range of Reynolds numbers. Research activities include deriving new mathematics of kernel functions for bottom-clamped and bendable cylinders, verifying and validating model output, investigating the relation between the drag force and the bending angle and the link between the lateral clearance in a cylinder cluster and the effectiveness of wave and surge attenuation, and upscaling the model to infer macroscale parameters for large-scale simulations to test hypotheses of wetland resilience and flood risk reduction. Three educational programs: Summer Outreach, Minority Internship, and Graduate Student Exchange, provide opportunities for communities and minorities to participate in research and inter-university collaborations.
Continued climate change and sea level rise pose a major threat to coastal habitats and communities worldwide. The impact of sea level rise has caused increased coastal erosion and flooding. For example, owing to subsidence, sea level rise and human interventions, the Mississippi River Delta and the Louisiana coast lose one acre of wetland every 24 minutes, which accounts for 80% of the total annual loss of coastal wetlands in the continental United States. The chronic wetland loss in south Louisiana has considerably weakened the natural defense against catastrophic floods, such as Hurricanes Katrina and Rita (2005). Over 1,500 people lost their lives and several major coastal populations were crippled for months after the hurricanes passed. Mitigating flood damage and reducing the threat of storm surges are imperative. It has been recognized that vegetation in wetlands can effectively reduce the flow speed. Results from the proposed research will not only provide insight to wave and surge attenuation in coastal wet-lands for coastal engineers and managers, but also serve as useful references for mechanical, civil, environmental, and ocean engineering concerning interactions of fluid with structures and plant canopies. The developed simulation tools will benefit society in better protecting the coastal ecosystem from impacts of storms and sea level rise and reducing the risk of flooding. Knowledge gained from the research will be assimilated in multi-channel education to train two graduate students, to involve minorities in mathematical science, and to stimulate the interest of communities in computational mathematics. This project will educate the public about the gravity of coastal flooding and erosion in Louisiana.