College of Education and Human Services
Master of Science in Civil Engineering (MSCE)
NACO controlled Corporate Body
University of North Florida. School of Engineering
Dr. Peter Bacopoulos
Dr. William R. Dally
Dr. Nick W. Hudyma
Dr. Murat M. Tiryakioglu
Dr. Mark A. Tumeo
A preexisting version of the 2D finite-element hydrodynamic model (code) ADCIRC was modified to enable assimilation of velocity data for calculation of longwave hydrodynamics of the lower St. Johns River. The data assimilation also enables model calibration and parameter estimation of directionally variant Manning’s n value using an anisotropic formulation of bottom roughness. This modified version of the ADCIRC code differs from the original ADCIRC model, as it introduces a module to provide evaluation of directional Manning’s roughness coefficient using observed velocity data for ebb and flood flow durations. The vector-based directional Manning’s n value is found by comparing the observed velocity data with the ADCIRC output from the original model dataset, depicting how the friction factor depends on flow direction. The modified ADCIRC model was calibrated for the velocity dataset and then validated with a different dataset of water surface elevation and streamflow. It is shown that the influence of the directional variability in bottom roughness is a significant factor in calibration of the model, especially given the to-and-fro nature of the tidal motions, which is contrary to present practices that ignore the temporal variability and any anisotropy in bottom roughness. This thesis makes a measured impact on how 2D hydrodynamic models (herein demonstrated with ADCIRC) are able to represent the directionality of bottom roughness in hydrodynamic simulation.
Demissie, Henok Kefelegn, "Bottom Friction Assessment for Hydrodynamic Currents in the Lower St. Johns River" (2015). UNF Graduate Theses and Dissertations. 570.