Subgrid Corrections in Finite-Element Modeling of Storm-Driven Coastal Flooding

Coastal flooding models are used to predict the timing and magnitude of inundation during storms, both for real-time forecasting and long-term design. However, there is a need for faster flooding predictions that also represent flow pathways and barriers at the scales of critical infrastructure. This need can be addressed via subgrid corrections, which use information at smaller scales to ‘correct’ the flow variables (water levels, current velocities) averaged over the mesh scale. Recent studies have shown a decrease in run time by 1 to 2 orders of magnitude, with the ability to decrease further if the model time step is also increased. In this study, subgrid corrections are added to a widely used, finite-element-based, shallow water model to better understand how they can improve the accuracy and efficiency of inundation predictions. The performance of the model, with and without subgrid corrections, is evaluated on scenarios of tidal flooding in a synthetic domain and a small bay in Massachusetts, as well as a scenario with a real atmospheric forcing and storm surge in southwest Louisiana. In these tests we observed that the subgrid corrections can increase model speed by 10 to 50 times, while still representing flow through channels below the mesh scale to inland locations.

JL Woodruff, JC Dietrich, D Wirasaet, AB Kennedy, D Bolster, Z Silver, SD Medlin, RL Kolar (2021). “Subgrid corrections in finite-element modeling of storm-driven coastal flooding.” Ocean Modelling, 167, 101887, DOI: 10.1016/j.ocemod.2021.101887.

Johnathan Woodruff wins First Place in Student Presentation Competition

Ph.D. student Johnathan Woodruff won first place in the student presentation competition during the annual Environmental, Water Resources, and Coastal Engineering Research Symposium. This award is chosen by judges from among all of the student presentations and is reflective of both compelling research activities and excellent presentation skills. The award includes a $500 cash stipend.

Congratulations to Johnathan!

CCHT Ph.D. student Johnathan Woodruff.

Virtual Conference: EWC Symposium 2021

BA Rumbaugh, JC Dietrich. “Impact of storm events on density stratification in the Pamlico and Albemarle Estuarine System.Environmental, Water Resources, and Coastal Engineering Research Symposium, North Carolina State University, 26 February 2021.

JL Woodruff, JC Dietrich, AB Kennedy, D Wirasaet, D Bolster, Z Silver, S Medlin, RL Kolar. “Finite Element Shallow Water Flow Model with Subgrid Corrections for Efficient Predictions of Storm-Driven Coastal Flooding.Environmental, Water Resources, and Coastal Engineering Research Symposium, North Carolina State University, 26 February 2021.

Virtual Conference: ASBPA Coastal Conference 2020