Evaluation of a Numerical Model for Wave-and Wind-induced Nearshore Circulation Using Field Data PDF Download

Author: J. H. Allender
Publisher:
ISBN:
Category : Coast changes
Languages : en
Pages : 150

View

Book Description

Author: William Allen Birkemeier
Publisher:
ISBN:
Category : Atmospheric circulation
Languages : en
Pages : 196

View

Book Description

Author: James Thornton Kirby
Publisher:
ISBN:
Category : Mathematical models
Languages : en
Pages : 182

View

Book Description
This report represents a review and conclusion of several studies conducted at the University of Delaware with the aim of providing numerical model for calculating nearshore wave-induces currents and mean water level fluctuations. The purpose of constructing a numerical model rests on the need to extend our predictive capabilities into situations which lie beyond the scope of analytic methods. In the end, all numerical models, as well as analytical formulations, are limited in scope by the simplifying assumptions incorporated in their theoretical framework; in this regard, the present models represent an attempt to extend present analytic treatments to the case of a complex topography in two dimensions. The models do not consider the associated sediment transport problem, although this capability can be added. Also, the models require that the incident wave field be regarded as monochromatic, or, after some model modifications, narrow banded enough to be represented as a modulated wave train at a single carrier frequency.

Author: Argonne National Laboratory. Energy and Environmental Systems Division
Publisher:
ISBN:
Category : Environmental protection
Languages : en
Pages : 112

View

Book Description

Author: Argonne National Laboratory. Energy and Environmental Systems Division
Publisher:
ISBN:
Category : Pollution
Languages : en
Pages : 92

View

Book Description

Author:
Publisher:
ISBN:
Category : Government publications
Languages : en
Pages : 1388

View

Book Description

Author: Dennis James Whitford
Publisher:
ISBN:
Category : Banks (Oceanography)
Languages : en
Pages : 238

View

Book Description
Previous investigations of longshore currents have included simplifying assumptions and restriction (such as a planar beach, a steady and depth uniform flow, spatially-variant bed shear stress and turbulent momentum exchange, and the exclusion of surface wind stress. These assumptions are quantitatively investigated by calculating the relative importance of each term in the longshore momentum balance with an emphasis on the relative importance of wind forcing across the barred nearshore. Wind and wave forcing of longshore currents across a barred beach are examined using both a numerical model and field measurements. A local momentum balance was measured at various locations across the surf zone during the SUPERDUCK experiment held at the USACE CERC Field Research Facility, Duck, N.C. in October 1986. A moveable sled was instrumented with pressure, current, and wind sensors to measure the various terms in the longshore momentum equation. Stability-dependent atmospheric drag coefficients for the surf zone are determined from wind stress measurements acquired just beyond the surf zone and wind speed measurements acquired from an anemometer atop the 9 m sled mast. Breaking waves were visually identified and electronically marked on the data tapes. Keywords: Ocean currents; Air water interactions; Nearshore surf zone; Wind stress; Theses. (EDC).

Author: Coastal Engineering Research Center (U.S.)
Publisher:
ISBN:
Category : Coasts
Languages : en
Pages : 754

View

Book Description

Author: William Allen Birkemeier
Publisher:
ISBN:
Category : Atmospheric circulation
Languages : en
Pages : 128

View

Book Description
A finite difference model for predicting time-dependent, wave-induced nearshore circulation is discussed. The formulation includes wave refraction, wave-current interaction, an anistropic bottom friction, wave set-up, wind effects and coastal flooding. Results are shown for three cases including: set-up in a wave channel due to steady waves and wave groups, circulation in a rectangular wave tank under oblique wave attack, and for wave and wind induced circulation on a longshore periodic beach. Important results are that tuned wave groups can incite seiching in an enclosed basin and harbors and that rip currents will be induced or maintained by the presence of surf zone channels. (Author).

Author: Bruce Alan Ebersole
Publisher:
ISBN:
Category : Atmospheric circulation
Languages : en
Pages : 104

View

Book Description
A finite difference model for predicting the nearshore circulation due to wind and waves is presented which attempts to solve the same problem as an earlier model created by Birkemeier and Dalrymple (1975). Their model iteratively solved the linear set of conservation equations of both mass and momentum, which were time averaged (over one wave period) and depth integrated, for mean velocities and free surface displacements. The wave characteristics used in the momentum equations were found using the wave refraction and shoaling routines, including wave-current interaction, developed by Noda, et al. (1974). The model also included a linear bottom friction formulation as well as a surface wind stress capability. The present model discussed herein includes the addition of convective accelerations, horizontal mixing and a quadratic bottom friction term in the conservation of momentum equations. This bottom friction term is 'exact' in the sense that it includes the velocity vectors due to both mean and wave-induced currents. The model is applied to the cases of a single wave train impinging on a plane beach, a barred profile, and a bottom with a periodically spaced rip channel.