Three Dimensional Simulation of Wave Induced Circulation

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Material Information

Title:
Three Dimensional Simulation of Wave Induced Circulation
Physical Description:
1 online resource (133 p.)
Language:
english
Creator:
Liu, Tianyi
Publisher:
University of Florida
Place of Publication:
Gainesville, Fla.
Publication Date:

Thesis/Dissertation Information

Degree:
Doctorate ( Ph.D.)
Degree Grantor:
University of Florida
Degree Disciplines:
Coastal and Oceanographic Engineering, Civil and Coastal Engineering
Committee Chair:
SHENG,YEAYI P
Committee Co-Chair:
SHEREMET,ALEXANDRU AURICA
Committee Members:
HATFIELD,KIRK
ADAMS,PETER N

Subjects

Subjects / Keywords:
oil-spill -- radiation-stress -- three-dimensional -- turbulence -- vortex-force -- wave-induced-circulation
Civil and Coastal Engineering -- Dissertations, Academic -- UF
Genre:
Coastal and Oceanographic Engineering thesis, Ph.D.
bibliography   ( marcgt )
theses   ( marcgt )
government publication (state, provincial, terriorial, dependent)   ( marcgt )
born-digital   ( sobekcm )
Electronic Thesis or Dissertation

Notes

Abstract:
In this study, a three-dimensional current-wave modeling system, CH3D-SWAN, has been improved on representing wave induced turbulence and wave induced circulation. Using the current-wave modeling system CH3D-SWAN and the storm surge modeling system CH3D-SSMS, the transport and fate of oil spill under wave induced circulation are assessed with an oil spill model. This study examines the role of turbulence modeling in simulating wave induced circulation. Specifically, performances of two turbulence models are compared: the first being a Turbulent Kinetic Energy model (TKEM) and the second being an EQuilibrium model (EQM), with both derived from a Reynolds Stress second order closure model. The TKEM carries a dynamic equation for q2 which is equivalent to twice the turbulent kinetic energy k, while the EQM assumes local equilibrium for all second order correlations, and hence the production balances dissipation locally. Both TKEM and EQM use a set of algebraic constraints or a dynamic equation to represent the turbulent macroscale. The TKEM allows the addition of a roller term at the top layer of the water column to account for turbulence induced by wave roller, while the EQM modifies the turbulent eddy coefficients by adding a vertically uniform roller term. The current-wave modeling system CH3D-SWAN with different turbulence models and the depth dependent radiation stress developed by Mellor (2008) is used to simulate wave induced circulation measured by Ting and Kirby (1994) (TK94). Model results show the TKEM with roller term added at the surface and algebraic constraints produces most accurate wave induced currents and turbulence, among all the turbulence formulations. The algebraic constraint equation gives more accurate results than the dynamic equation for turbulent macroscale. Using the TKEM including wave roller dynamics and algebraic constraints for turbulent macroscale, storm surge modeling system CH3D-SSMS produces similar storm surge during Hurricane Isabel, while improves the simulated currents, in comparison to that obtained previously using the EQM.   The three-dimensional current-wave modeling system, CH3D- SWAN, has been used to simulate wave induced circulation and compare the performances of depth dependent radiation stress formulations (M08 and M13 by Mellor (2008, 2013)) and a vortex force formulation (MRL04 by McWilliams et al. (2004)). M13 is similar to a problematic radiation stress (X04 by Xia et al. (2004)) in shallow water, and generates inaccurate wave induced currents compared with observations by TK94.MRL04 accurately simulates wave setup and turbulent kinetic energy observed in TK94, and improves simulated currents outside the surf zone compared with M08.The cross-shore flow gyre produced by MRL04 is mainly located inside the surf zone, while M08 generates a flow gyre extending to slope edge and overestimates currents outside the surf zone, due probably to the singular pressure term which is derived in Eulerian frame but incorporated in Lagrangian momentum equations. On the inner shelf, both MRL04 and M08produce cross-shore velocity profiles similar to Stokes drift with an opposite direction, but M08 generates zero flow in along-shelf direction, which is inconsistent with observation. MRL04 leads to successful simulation of observed Langmuir circulation in laboratory experiments and captures higher order wave induced circulation than M08 which is not able to simulate Langmuir circulation. Using MRL04, CH3D-SSMS produces higher wave setup which compares better with observed water level during Hurricane Isabel than that using M08, and simulated currents are slightly improved. An oil spill model is developed and coupled to a current-wave model to simulate oil spill transport in aquatic environments where waves are present. The oil spill model incorporates physical-chemical processes of oil spill, and simulates oil slick transport by a circulation-driven Lagrangian Parcel model. Using the coupled oil spill model and the current-wave model CH3D-SWAN, a laboratory observed wave induced circulation and oil slick evolution are successfully simulated, while different current-wave coupling schemes generate different flow patterns and oil slick evolution. The modeling system is also shown to simulate Langmuir circulation and resulting oil slicks. Hypothetical scenarios of oil spill near Virginia coast during Hurricane Isabel and Irene are simulated using the oil spill model andCH3D-SSMS to assess the role of storm waves during oil spill. The spill area is significantly larger when storm waves are considered, implying waves significantly increase oil spill dispersion.
General Note:
In the series University of Florida Digital Collections.
General Note:
Includes vita.
Bibliography:
Includes bibliographical references.
Source of Description:
Description based on online resource; title from PDF title page.
Source of Description:
This bibliographic record is available under the Creative Commons CC0 public domain dedication. The University of Florida Libraries, as creator of this bibliographic record, has waived all rights to it worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law.
Statement of Responsibility:
by Tianyi Liu.
Thesis:
Thesis (Ph.D.)--University of Florida, 2013.
Local:
Adviser: SHENG,YEAYI P.
Local:
Co-adviser: SHEREMET,ALEXANDRU AURICA.
Electronic Access:
RESTRICTED TO UF STUDENTS, STAFF, FACULTY, AND ON-CAMPUS USE UNTIL 2015-12-31

Record Information

Source Institution:
UFRGP
Rights Management:
Applicable rights reserved.
Classification:
lcc - LD1780 2013
System ID:
UFE0046111:00001