Electronic Theses and Dissertations

Date of Award

2016

Document Type

Thesis

Degree Name

M.S. in Engineering Science

Department

Mechanical Engineering

First Advisor

Yan Ding

Second Advisor

Yafei Jia

Relational Format

dissertation/thesis

Abstract

The eastern and southern coastlines of the United States are two of the most cyclone-prone areas of the world. The effects of tropical cyclones vary mainly depending on wind intensity and geological features of the coast that it is crossing. Higher winds potentially generate higher storm surges and consequently larger floods occur along the coastlines. Therefore, it is critical to accurately predict winds, storm surge, and waves associated with a hurricane. In the present study, an integrated coastal and ocean process model, CCHE2D-Coast, is validated by assessing the model’s capabilities in simulating coast-ocean circulations driven by the astronomical tides on the U.S. East Coast. Through the skill assessment, discrepancies between numerically simulated water surface elevations and observed tidal elevations at NOAA tide gages are quantified. On the other hand, statistical errors of the tidal constituents parameters, amplitude and phase, are also determined. In this study, the tidal harmonic constants are identified by using a newly-developed parameter identification approach. CCHE2D-Coast is also further examined under meteorological forces driven by a hurricane. CCHE2D-Coast is applied to simulate meteorological and hydrodynamic processes during Hurricane Bob (1991) on the US Atlantic coast. Hindcasting storm surges and waves induced by Bob’s winds and tides were performed before and after the landfall of this hurricane. The results shothat the model performed well in reproducing the dynamic process driven by astronomical and meteorological forces. To improve the model’s accuracy in reproducing hurricane wind fields during a real-time hurricane forecast, a hurricane wind model is developed in order to incorporate asymmetric effects into the Holland parametric wind model. The method is validated using the National Oceanic and Atmospheric Administration (NOAA)/ National Hurricane Center (NHC)/ Automated Tropical Cyclone Forecast’s (ATCF) guidelines. The best track date, which contains six-hourly information on the location, maximum winds, radii of 3 wind isotach, and central pressure of Hurricane Gustave (2008) is used to compute the wind field in the Gulf of Mexico. The simulation result suggests that the wind model performed well in reconstructing wind field. The asymmetric model captured the directional change of hurricane wind velocity around the storm center.

Concentration/Emphasis

Emphasis: Computational Hydroscience

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