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Richard A Luettich - One of the best experts on this subject based on the ideXlab platform.

  • developing a Tidal Constituent database for the eastern north pacific ocean
    Estuarine and Coastal Modeling. Eighth International ConferenceAmerican Society of Civil Engineers, 2004
    Co-Authors: Emily Spargo, Richard A Luettich, Joannes J Westerink, Dave Mark
    Abstract:

    This paper describes the development of the Eastern North Pacific (ENPAC) 2003 Tidal database of the elevations and velocity components of eight manor Tidal Constituents. This database was developed using the two-dimensional, depth integrated from the coastal hydrodynamic model, ADIRC, which consists of the shallow water equations in the generalized wave continuity equation from. The final ENPAC 2003 model incorporates the most accurate bathmymetric data available. The resolution of the unstructured finite element mesh was designed to provide high levels of resolution along the continental slope and throughout the coastal waters to resolve the non-linear hydrodynamics that dominate the area. The domain of this model extends beyond the continental shelf, into deep ocean waters but does not include any amphidromes located in the Pacific Ocean. At the open boundary, the forcing conditions are extracted from global ocean models, in the area where these models are most accurate. A brief discussion comparing the results from the global ocean models with the results from the ADCIRC model is included in this paper. The results of the ENPAC 2003 model are approaching the error levels found in the station data that is used for model validation.

  • enpac 2003 a Tidal Constituent database for eastern north pacific ocean
    This Digital Resource was created from scans of the Print Resource., 2004
    Co-Authors: David J Mark, Emily Spargo, Joannes J Westerink, Richard A Luettich
    Abstract:

    Abstract : This report describes the development of the Eastern North Pacific (ENPAC) 2003 Tidal database of elevations and velocity components for eight major Tidal Constituents. This database was developed using the two-dimensional, depth-integrated form of the coastal hydrodynamic model, ADCIRC, which solves the shallow-water equations in the generalized wave continuity equation form. The final ENPAC 2003 incorporates the most accurate bathymetric data available. The resolution of the unstructured finite element mesh was designed to provide a high level of resolution along the continental slope and throughout the coastal waters to resolve the nonlinear hydrodynamics that dominate this area. The domain of this model extends beyond the continental shelf into deep ocean waters, but does not include any amphidromes located in the Pacific Ocean. At the open boundary, the forcing conditions are extracted from global ocean models, in the area where these models are most accurate. The results of the ENPAC 2003 model approach the error levels found in the station data that were used for model validation. (6 tables, 187 figures, 36 refs.)

  • eastcoast 2001 a Tidal Constituent database for western north atlantic gulf of mexico and caribbean sea
    This Digital Resource was created from scans of the Print Resource., 2002
    Co-Authors: A Y Mukai, Richard A Luettich, Joannes J Westerink, David J Mark
    Abstract:

    Abstract : This report describes the development of the Eastcoast 2001 database of computed Tidal elevation and velocity Constituents within the Western North Atlantic Tidal (WNAT) domain. The WNAT domain encompasses the Western North Atlantic Ocean, Gulf of Mexico, and Caribbean Sea. The computations are based on a strategically designed finite element grid and the coastal hydrodynamic circulation model, ADCIRC. The resulting Eastcoast 2001 database defines the computed elevation and velocity amplitude and phase for the O1, K1, Q1, M2, S2, N2, and K2 Tidal Constituents. The Eastcoast 2001 database is significantly more accurate than the previous Eastcoast 1995 and Eastcoast 1991 databases based on the following feature improvements: (a) a new grid generation technique with better node placement and distribution, (b) a significantly greater number of total nodes, (c) a more accurate coastal boundary, and (d) inclusion of more reliable bathymetric databases. The new grid generation technique is the combination of two a priori mesh criteria: (a) The wavelength to grid size ratio and (b) the topographic length scale criteria. This combination optimally and more accurately places grid nodes in areas where high resolution is needed. Error analysis of computed versus measured elevation amplitude and phase at 101 stations in addition to an assessment of measured data errors globally and locally quantifies The level of reliability of the computed Constituents.

  • adcirc an advanced three dimensional circulation model for shelves coasts and estuaries report 6 development of a Tidal Constituent database for the eastern north pacific
    1994
    Co-Authors: James L Hench, Richard A Luettich, Joannes J Westerink, Norman W Scheffner
    Abstract:

    Abstract : This report describes the application of ADCIRC-2DDI, a two-dimensional depth-averaged barotropic hydrodynamic model, to the eastern North Pacific in order to develop a Tidal Constituent database. Issues that are emphasized in the development of the Eastern North Pacific Tidal (ENPACT) model include the specification of a geometrically and hydrodynamically simple open boundary, the use of large domains, and the advantages of using a graded finite element grid to selectively resolve flow features of interest. The ENPACT model is coupled to a finite element global ocean model at the open boundary and forced with five diurnal and semidiurnal astronomical Tidal Constituents (K1, O1, M2, S2, and N2). Tidal potential forcing is applied to the interior of the domain for the same Constituents. The structures of the various tides are examined and the results of the Tidal simulations are compared with field data at 72 fixed Tidal elevation stations. (AN)

  • adcirc an advanced three dimensional circulation model for shelves coasts and estuaries report 3 development of a Tidal Constituent database for the western north atlantic and gulf of mexico
    1993
    Co-Authors: Joannes J Westerink, Richard A Luettich, Norman W Scheffner
    Abstract:

    Abstract : This report describes the application of model ADCIRC-2DDI, a two- dimensional, depth-integrated, finite-element-based hydrodynamic circulation code, to the western North Atlantic, Gulf of Mexico and Caribbean Sea in order to develop a Tidal Constituent database. Issues that are emphasized in the development of the Western North Atlantic Tidal (WNAT) model include the definition of hydrodynamically simple open ocean boundaries; the use of large domains; the importance of a high degree of grid resolution in coastal regions; and the use of finite element meshes with highly varying nodal densities in order to minimize the size of the discrete problem. The development of an optimal graded finite element mesh is based on regular and graded grid convergence studies using an M2 Tidal forcing function on the boundary and within the domain. The optimal graded mesh is then forced for eight diurnal and semidiurnal astronomical Tidal Constituents (K1, O1, PI, Ql, M2, S2, N2, and K2) on the open ocean boundary by coupling to Schwiderski's (1979; 1981 a-g) global model results as well as within the interior domain using a Tidal potential forcing function. The structure of the various tides is examined and results are compared to field data at 77 stations.... Bottom stress, Finite element method, Three-dimensional model, Circulation model, Hydrodynamic model, Two-dimensional model, Direct stress solution, Numerical model.

Joannes J Westerink - One of the best experts on this subject based on the ideXlab platform.

  • developing a Tidal Constituent database for the eastern north pacific ocean
    Estuarine and Coastal Modeling. Eighth International ConferenceAmerican Society of Civil Engineers, 2004
    Co-Authors: Emily Spargo, Richard A Luettich, Joannes J Westerink, Dave Mark
    Abstract:

    This paper describes the development of the Eastern North Pacific (ENPAC) 2003 Tidal database of the elevations and velocity components of eight manor Tidal Constituents. This database was developed using the two-dimensional, depth integrated from the coastal hydrodynamic model, ADIRC, which consists of the shallow water equations in the generalized wave continuity equation from. The final ENPAC 2003 model incorporates the most accurate bathmymetric data available. The resolution of the unstructured finite element mesh was designed to provide high levels of resolution along the continental slope and throughout the coastal waters to resolve the non-linear hydrodynamics that dominate the area. The domain of this model extends beyond the continental shelf, into deep ocean waters but does not include any amphidromes located in the Pacific Ocean. At the open boundary, the forcing conditions are extracted from global ocean models, in the area where these models are most accurate. A brief discussion comparing the results from the global ocean models with the results from the ADCIRC model is included in this paper. The results of the ENPAC 2003 model are approaching the error levels found in the station data that is used for model validation.

  • enpac 2003 a Tidal Constituent database for eastern north pacific ocean
    This Digital Resource was created from scans of the Print Resource., 2004
    Co-Authors: David J Mark, Emily Spargo, Joannes J Westerink, Richard A Luettich
    Abstract:

    Abstract : This report describes the development of the Eastern North Pacific (ENPAC) 2003 Tidal database of elevations and velocity components for eight major Tidal Constituents. This database was developed using the two-dimensional, depth-integrated form of the coastal hydrodynamic model, ADCIRC, which solves the shallow-water equations in the generalized wave continuity equation form. The final ENPAC 2003 incorporates the most accurate bathymetric data available. The resolution of the unstructured finite element mesh was designed to provide a high level of resolution along the continental slope and throughout the coastal waters to resolve the nonlinear hydrodynamics that dominate this area. The domain of this model extends beyond the continental shelf into deep ocean waters, but does not include any amphidromes located in the Pacific Ocean. At the open boundary, the forcing conditions are extracted from global ocean models, in the area where these models are most accurate. The results of the ENPAC 2003 model approach the error levels found in the station data that were used for model validation. (6 tables, 187 figures, 36 refs.)

  • eastcoast 2001 a Tidal Constituent database for western north atlantic gulf of mexico and caribbean sea
    This Digital Resource was created from scans of the Print Resource., 2002
    Co-Authors: A Y Mukai, Richard A Luettich, Joannes J Westerink, David J Mark
    Abstract:

    Abstract : This report describes the development of the Eastcoast 2001 database of computed Tidal elevation and velocity Constituents within the Western North Atlantic Tidal (WNAT) domain. The WNAT domain encompasses the Western North Atlantic Ocean, Gulf of Mexico, and Caribbean Sea. The computations are based on a strategically designed finite element grid and the coastal hydrodynamic circulation model, ADCIRC. The resulting Eastcoast 2001 database defines the computed elevation and velocity amplitude and phase for the O1, K1, Q1, M2, S2, N2, and K2 Tidal Constituents. The Eastcoast 2001 database is significantly more accurate than the previous Eastcoast 1995 and Eastcoast 1991 databases based on the following feature improvements: (a) a new grid generation technique with better node placement and distribution, (b) a significantly greater number of total nodes, (c) a more accurate coastal boundary, and (d) inclusion of more reliable bathymetric databases. The new grid generation technique is the combination of two a priori mesh criteria: (a) The wavelength to grid size ratio and (b) the topographic length scale criteria. This combination optimally and more accurately places grid nodes in areas where high resolution is needed. Error analysis of computed versus measured elevation amplitude and phase at 101 stations in addition to an assessment of measured data errors globally and locally quantifies The level of reliability of the computed Constituents.

  • adcirc an advanced three dimensional circulation model for shelves coasts and estuaries report 6 development of a Tidal Constituent database for the eastern north pacific
    1994
    Co-Authors: James L Hench, Richard A Luettich, Joannes J Westerink, Norman W Scheffner
    Abstract:

    Abstract : This report describes the application of ADCIRC-2DDI, a two-dimensional depth-averaged barotropic hydrodynamic model, to the eastern North Pacific in order to develop a Tidal Constituent database. Issues that are emphasized in the development of the Eastern North Pacific Tidal (ENPACT) model include the specification of a geometrically and hydrodynamically simple open boundary, the use of large domains, and the advantages of using a graded finite element grid to selectively resolve flow features of interest. The ENPACT model is coupled to a finite element global ocean model at the open boundary and forced with five diurnal and semidiurnal astronomical Tidal Constituents (K1, O1, M2, S2, and N2). Tidal potential forcing is applied to the interior of the domain for the same Constituents. The structures of the various tides are examined and the results of the Tidal simulations are compared with field data at 72 fixed Tidal elevation stations. (AN)

  • adcirc an advanced three dimensional circulation model for shelves coasts and estuaries report 3 development of a Tidal Constituent database for the western north atlantic and gulf of mexico
    1993
    Co-Authors: Joannes J Westerink, Richard A Luettich, Norman W Scheffner
    Abstract:

    Abstract : This report describes the application of model ADCIRC-2DDI, a two- dimensional, depth-integrated, finite-element-based hydrodynamic circulation code, to the western North Atlantic, Gulf of Mexico and Caribbean Sea in order to develop a Tidal Constituent database. Issues that are emphasized in the development of the Western North Atlantic Tidal (WNAT) model include the definition of hydrodynamically simple open ocean boundaries; the use of large domains; the importance of a high degree of grid resolution in coastal regions; and the use of finite element meshes with highly varying nodal densities in order to minimize the size of the discrete problem. The development of an optimal graded finite element mesh is based on regular and graded grid convergence studies using an M2 Tidal forcing function on the boundary and within the domain. The optimal graded mesh is then forced for eight diurnal and semidiurnal astronomical Tidal Constituents (K1, O1, PI, Ql, M2, S2, N2, and K2) on the open ocean boundary by coupling to Schwiderski's (1979; 1981 a-g) global model results as well as within the interior domain using a Tidal potential forcing function. The structure of the various tides is examined and results are compared to field data at 77 stations.... Bottom stress, Finite element method, Three-dimensional model, Circulation model, Hydrodynamic model, Two-dimensional model, Direct stress solution, Numerical model.

Paolo Blondeaux - One of the best experts on this subject based on the ideXlab platform.

  • Tidal sand wave formation influence of graded suspended sediment transport
    Journal of Geophysical Research, 2009
    Co-Authors: T Van Oyen, Paolo Blondeaux
    Abstract:

    [1] The influence of graded suspended sediment transport on the formation of Tidal sand waves is investigated. Hereto, in the framework of a linear stability analysis, we examine the time development of small-amplitude perturbations superimposed to a flat heterogeneous seabed in a shallow Tidal sea dominated by one Tidal Constituent. The heterogeneous bottom material is modeled by a bimodal sediment mixture and the transport of sediment close to the bottom, as well as in suspension, is considered. The active layer concept is employed and hiding/exposure effects are taken into account. The mechanisms giving rise to the sediment-sorting process along the bed forms are found to be unaffected by the fractional transport of sediment in suspension. On the other hand, the formation of sand waves is quantitatively, substantially affected by the graded suspended sediment transport and the wavelength of the most amplified mode is found to depend strongly on the characteristics of the sediment mixture. In particular, the graded suspended sediment transport largely affects the contribution to the amplification rate related to the sorting process. This leads to the growth of bed forms characterized by a smaller wavelength compared with that predicted for a uniform sediment, when the mean grain size of the sediment mixture is relatively coarse. On the other hand, longer bed forms appear when the sediment mixture is characterized by a relatively fine mean grain size. Moreover, a destabilizing effect is identified in the former case while the flat bed configuration is stabilized in the latter case. A comparison of the theoretical predictions with field observations seems to support the model, even though it cannot be considered conclusive.

  • grain sorting effects on the formation of Tidal sand waves
    Marine Sandwave and River Dune Dynamics III (MARID 2008), 2008
    Co-Authors: T Van Oyen, Paolo Blondeaux
    Abstract:

    A model is developed to investigate the process which leads to the formation of sand waves in shallow Tidal seas characterized by a heterogeneous sea bed composition. The main goal of the analysis is the evaluation of the effects that a graded sediment has on the formation of the bottom forms and the investigation of the sorting process induced by the growth of the bottom forms. The analysis is based on the study of the stability of the flat bed configuration, i.e. small amplitude perturbations are added to the flat bottom and a linear analysis of their time development is made. For an oscillatory Tidal current dominated by one Tidal Constituent, the results show that the graded sediment can stabilize or destabilize the flat bottom configuration with respect to the uniform sediment case, depending on the standard deviation sigma* of the grain size distribution and on the ratio (r) over cap between the horizontal Tidal excursion and the water depth. For moderate values of (r) over cap, i.e. values just larger than the critical value for which the sediment is moved and sand waves appear, the presence of a sand mixture stabilizes the flat bed. On the other hand, for large values or (r) over cap, the mixture has a destabilizing effect. In both cases the effect that a sand Mixture has on the stability of the flat bed configuration is relatively small. Moreover, for moderate values of (r) over cap, the fine fraction of the mixture tends to pile up at the crests of the bottom forms while the coarse fraction moves towards the troughs. For large values or (r) over cap, the grain size distribution depends on the value of sigma*. The results are physically interpreted and provide a possible explanation of the apparently conflicting field observations of the grain size distribution along the sand wave profile, carried Out in the North Sea.

Norman W Scheffner - One of the best experts on this subject based on the ideXlab platform.

  • adcirc an advanced three dimensional circulation model for shelves coasts and estuaries report 6 development of a Tidal Constituent database for the eastern north pacific
    1994
    Co-Authors: James L Hench, Richard A Luettich, Joannes J Westerink, Norman W Scheffner
    Abstract:

    Abstract : This report describes the application of ADCIRC-2DDI, a two-dimensional depth-averaged barotropic hydrodynamic model, to the eastern North Pacific in order to develop a Tidal Constituent database. Issues that are emphasized in the development of the Eastern North Pacific Tidal (ENPACT) model include the specification of a geometrically and hydrodynamically simple open boundary, the use of large domains, and the advantages of using a graded finite element grid to selectively resolve flow features of interest. The ENPACT model is coupled to a finite element global ocean model at the open boundary and forced with five diurnal and semidiurnal astronomical Tidal Constituents (K1, O1, M2, S2, and N2). Tidal potential forcing is applied to the interior of the domain for the same Constituents. The structures of the various tides are examined and the results of the Tidal simulations are compared with field data at 72 fixed Tidal elevation stations. (AN)

  • Tidal Constituent database east coast gulf of mexico and caribbean sea
    1994
    Co-Authors: Norman W Scheffner
    Abstract:

    Abstract : This technical note describes a database of Tidal elevation boundary conditions generated in Support of Long Term Fate of Dredged Material Disposed in Open Water research of the Dredging Research Program (DRP), being conducted by the U.S. Army Engineer Waterways experiment Station (WES). The database described allows the user to manually generate time series of Tidal elevations or to use a program to access the full database to generate time series of both tide elevations and currents for any location along the U.S. east coast, Gulf of Mexico and Caribbean Sea. Although the capability to generate these time series was developed to provide input to the long term fate and stability model LTFATE, the generated time series can be used for any application requiring Tidal forcing data.

  • adcirc an advanced three dimensional circulation model for shelves coasts and estuaries report 3 development of a Tidal Constituent database for the western north atlantic and gulf of mexico
    1993
    Co-Authors: Joannes J Westerink, Richard A Luettich, Norman W Scheffner
    Abstract:

    Abstract : This report describes the application of model ADCIRC-2DDI, a two- dimensional, depth-integrated, finite-element-based hydrodynamic circulation code, to the western North Atlantic, Gulf of Mexico and Caribbean Sea in order to develop a Tidal Constituent database. Issues that are emphasized in the development of the Western North Atlantic Tidal (WNAT) model include the definition of hydrodynamically simple open ocean boundaries; the use of large domains; the importance of a high degree of grid resolution in coastal regions; and the use of finite element meshes with highly varying nodal densities in order to minimize the size of the discrete problem. The development of an optimal graded finite element mesh is based on regular and graded grid convergence studies using an M2 Tidal forcing function on the boundary and within the domain. The optimal graded mesh is then forced for eight diurnal and semidiurnal astronomical Tidal Constituents (K1, O1, PI, Ql, M2, S2, N2, and K2) on the open ocean boundary by coupling to Schwiderski's (1979; 1981 a-g) global model results as well as within the interior domain using a Tidal potential forcing function. The structure of the various tides is examined and results are compared to field data at 77 stations.... Bottom stress, Finite element method, Three-dimensional model, Circulation model, Hydrodynamic model, Two-dimensional model, Direct stress solution, Numerical model.

  • adcirc an advanced three dimensional circulation model for shelves coasts and estuaries report 3 development of a Tidal Constituent database for the western north atlantic and gulf of mexico technical report
    1993
    Co-Authors: Joannes J Westerink, Richard A Luettich, Norman W Scheffner
    Abstract:

    This report describes the application of model ADCIRC-2DDI, a two-dimensional, depth-integrated, finite-element-based hydrodynamic circulation code, to the western North Atlantic, Gulf of Mexico and Caribbean Sea in order to develop a Tidal Constituent database. Issues that are emphasized in the development of the Western North Atlantic Tidal (WNAT) model include the definition of hydrodynamically simple open ocean boundaries; the use of large domains; the importance of a high degree of grid resolution in coastal regions; and the use of finite element meshes with highly varying nodal densities in order to minimize the size of the discrete problem. The development of an optimal graded finite element mesh is based on regular and graded grid convergence studies using an M2 Tidal forcing function on the boundary and within the domain. The optimal graded mesh is then forced for eight diurnal and semidiurnal astronomical Tidal Constituents (K1, O1, PI, Ql, M2, S2, N2, and K2) on the open ocean boundary by coupling to Schwiderski's (1979; 1981 a-g) global model results as well as within the interior domain using a Tidal potential forcing function. The structure of the various tides is examined and results are compared to field data at 77 stations.... Bottom stress,more » Finite element method, Three-dimensional model, Circulation model, Hydrodynamic model, Two-dimensional model, Direct stress solution, Numerical model.« less

T Van Oyen - One of the best experts on this subject based on the ideXlab platform.

  • Tidal sand wave formation influence of graded suspended sediment transport
    Journal of Geophysical Research, 2009
    Co-Authors: T Van Oyen, Paolo Blondeaux
    Abstract:

    [1] The influence of graded suspended sediment transport on the formation of Tidal sand waves is investigated. Hereto, in the framework of a linear stability analysis, we examine the time development of small-amplitude perturbations superimposed to a flat heterogeneous seabed in a shallow Tidal sea dominated by one Tidal Constituent. The heterogeneous bottom material is modeled by a bimodal sediment mixture and the transport of sediment close to the bottom, as well as in suspension, is considered. The active layer concept is employed and hiding/exposure effects are taken into account. The mechanisms giving rise to the sediment-sorting process along the bed forms are found to be unaffected by the fractional transport of sediment in suspension. On the other hand, the formation of sand waves is quantitatively, substantially affected by the graded suspended sediment transport and the wavelength of the most amplified mode is found to depend strongly on the characteristics of the sediment mixture. In particular, the graded suspended sediment transport largely affects the contribution to the amplification rate related to the sorting process. This leads to the growth of bed forms characterized by a smaller wavelength compared with that predicted for a uniform sediment, when the mean grain size of the sediment mixture is relatively coarse. On the other hand, longer bed forms appear when the sediment mixture is characterized by a relatively fine mean grain size. Moreover, a destabilizing effect is identified in the former case while the flat bed configuration is stabilized in the latter case. A comparison of the theoretical predictions with field observations seems to support the model, even though it cannot be considered conclusive.

  • grain sorting effects on the formation of Tidal sand waves
    Marine Sandwave and River Dune Dynamics III (MARID 2008), 2008
    Co-Authors: T Van Oyen, Paolo Blondeaux
    Abstract:

    A model is developed to investigate the process which leads to the formation of sand waves in shallow Tidal seas characterized by a heterogeneous sea bed composition. The main goal of the analysis is the evaluation of the effects that a graded sediment has on the formation of the bottom forms and the investigation of the sorting process induced by the growth of the bottom forms. The analysis is based on the study of the stability of the flat bed configuration, i.e. small amplitude perturbations are added to the flat bottom and a linear analysis of their time development is made. For an oscillatory Tidal current dominated by one Tidal Constituent, the results show that the graded sediment can stabilize or destabilize the flat bottom configuration with respect to the uniform sediment case, depending on the standard deviation sigma* of the grain size distribution and on the ratio (r) over cap between the horizontal Tidal excursion and the water depth. For moderate values of (r) over cap, i.e. values just larger than the critical value for which the sediment is moved and sand waves appear, the presence of a sand mixture stabilizes the flat bed. On the other hand, for large values or (r) over cap, the mixture has a destabilizing effect. In both cases the effect that a sand Mixture has on the stability of the flat bed configuration is relatively small. Moreover, for moderate values of (r) over cap, the fine fraction of the mixture tends to pile up at the crests of the bottom forms while the coarse fraction moves towards the troughs. For large values or (r) over cap, the grain size distribution depends on the value of sigma*. The results are physically interpreted and provide a possible explanation of the apparently conflicting field observations of the grain size distribution along the sand wave profile, carried Out in the North Sea.