A comparative study of three mathematical models for wind-generated circulation in coastal areas

Koutitas, C.; Gousidou-Koutita, M.

doi:10.1016/0378-3839(86)90013-x

Cited by 17 publications

(5 citation statements)

References 2 publications

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“…Two-dimensional (2D) depth-averaged models were employed to address the horizontal circulation and temperature dynamics [23,34]. Further efforts have been paid to incorporate the vertical variation of horizontal velocities in the depth-integrated models [35,36], but the vertical stratification has yet to be addressed. Lin and Wu [37,38] and Lin [39] examined thermally-driven flows over vegetated sloping bottoms with an idealized, linear, vertically-solved slice analytical model.…”

Section: Introductionmentioning

confidence: 99%

Temperature and Circulation Dynamics in a Small and Shallow Lake: Effects of Weak Stratification and Littoral Submerged Macrophytes

Torma

2019

Water

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In this paper, the effects of littoral submerged macrophytes on weak stratification conditions in a small and shallow lake are investigated. Diverse submerged macrophytes occupying a large portion of the littoral zone act as resistance to water motions and affect lake hydrodynamics. Strong solar radiation and mild wind forcing typically occurring during the summer season result in weak stratification characterized by a diurnal cycle with a temperature differential of 1-3 • C. Temperature and circulation dynamics of a small and shallow lake are depicted by extensive field measurements and a three-dimensional non-hydrostatic model with a generic length scale (GLS) approach for the turbulence closure and drag forces induced by macrophytes. Results show that the effects of macrophytes on velocity profiles are apparent. In the pelagic area, the circulation patterns with and without macrophytes are similar. The velocity profile is generally characterized by a two-layer structure with the maximum velocity at both the water surface and the mid-depth. In contrast, inside the littoral zone, the mean flow is retarded by macrophytes and the velocity profile is changed to only one maximum velocity at the surface with a steeper decrease until 2.0 m depth and another slight decrease to the lake bottom. From the whole lake perspective, littoral macrophytes dampen the horizontal water temperature difference between the upwind side and download side of the lake. Macrophytes promote a stronger temperature stratification by retarding mean flows and reducing vertical mixing. Overall, this study shows that the temperature structures and circulation patterns under weak stratification conditions in a small and shallow lake are strongly affected by littoral vegetation.

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Section: Introductionmentioning

confidence: 99%

Temperature and Circulation Dynamics in a Small and Shallow Lake: Effects of Weak Stratification and Littoral Submerged Macrophytes

Torma

2019

Water

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“…The present hydraulic force model uses a new hydrodynamic force equation based on the energy approach given by: (7) in which F is the total hydrodynamic force exerted by the ocean currents, surge, and waves, ζT is the total flood level or total sea surface elevation consisting of the surface waves and the storm surge, ρ is the density of seawater, Nz is the buoyancy frequency assumed constant, and u and v are the mean current components along x and y axes, respectively. At mid-depth, the ocean currents have a magnitude that is almost equivalent to the mean-depth currents u and v. However, at the surface, the magnitude of the current velocity becomes very strong which is over 1.5 times the mean-depth current (i.e., Koutitas and Koutita [1986] method). Even during the occurrence of average storms with 120 kph (< 65 knots) winds, this can result in a largescale damage of breakwaters and other coastal structures including seawalls and coastal roads.…”

Section: Hydraulic Force Due To Current and Wave Actionmentioning

confidence: 99%

A Dispersive Long-Wave Model for Predicting Coastal Flooding Due to Storm Surges and Surface Waves in Manila Bay

Rivera¹

2022

Preprint

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Manila Bay is a large shallow coastal water encompassing the urban areas of Metro Manila and various cities of sub-urban provinces in the Philippines. It is a relatively shallow semi-enclosed basin with an average depth of 20m whose coastal areas are crowded with residential, industrial, agricultural and aquaculture production. Its shallow depths imply that the effect of wind stress on sea level becomes appreciable in driving storm surges even during enhanced Southwest Monsoon and the passage of moderate storms. Using a dispersive long wave model coupled with the significant wave model of the Coastal Engineering Research Center (CERC), the occurrence of potentially devastating storm surge flooding around Manila Bay was numerically simulated. A unique characteristic of the new model is the inclusion of the dispersive terms in the associated momentum balance equations. Deep water gravity waves are always dispersive and inclusion of the dispersive terms is expected to provide more accurate modelling results.The predictive capability of the model was verified using observations during the passage of several storms including Typhoon Milenyo (2006) and Typhoon Pedring (2011). The occurrence of the anomalously high storm surge of about 2.5 meters during the passage of 2011 Typhoon Pedring far north of the area was correctly simulated. Numerical integration of the dispersive long wave model with the addition of higher order terms in the momentum balance, appears to give accurate predictions of the coastal flooding due to storm surges and waves. The hydrodynamic set-down which occurs in many coastal areas during strong typhoons can be simulated well by the model. A new empirical model for the hydrodynamic force exerted by the combined action of storm surges, waves and extreme currents is also presented. Initial calculations of hydrodynamic forces generated by an actual typhoon crossing Manila Bay are discussed.

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“…Dispersion can be simulated using a Monte-Carlo randomwalk approach. The random displacement evaluated by random numbers and horizontal dispersion coefficients are added to the movement computed from the flow field (Leendertse and Liu, 1977;Koutitas and Gousidou-Koutita, 1986). The equations governing the current-induced particle motions are:…”

Section: A Particle Trajectory Modelmentioning

confidence: 99%

Application and Verification of a three-dimensional Hydrodynamic Model to Hamilton Harbour, Canada

Edinger¹,

Tsanis²,

Wu³

2013

Global NEST Journal

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A multi-layered three-dimensional hydrodynamic model has been developed to provide flow fields and water level changes in Hamilton Harbour. The field data collected in Hamilton Harbour during 1990 & 1991 field seasons was used for model verification. The simulated currents were compared with current meter data. Results from the trajectory model are in good agreement with the drogue experimental data. A quantitative criterion to evaluate the trajectory comparison was established with the help of the trajectory model using the random-walk approach. By using the water level changes in the Burlington Ship Canal, the model predictions were validated with the measurements at three water level stations in the Harbour. These comparisons demonstrate that the models can simulate the major features of the water current and level changes in Hamilton Harbour.

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A comparative study of three mathematical models for wind-generated circulation in coastal areas

Cited by 17 publications

References 2 publications

Temperature and Circulation Dynamics in a Small and Shallow Lake: Effects of Weak Stratification and Littoral Submerged Macrophytes

Temperature and Circulation Dynamics in a Small and Shallow Lake: Effects of Weak Stratification and Littoral Submerged Macrophytes

A Dispersive Long-Wave Model for Predicting Coastal Flooding Due to Storm Surges and Surface Waves in Manila Bay

Application and Verification of a three-dimensional Hydrodynamic Model to Hamilton Harbour, Canada

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