Explicit wave-averaged primitive equations using a generalized Lagrangian mean

Ardhuin, F; Rascle, N; Belibassakis, KA

dc.contributor.author	Ardhuin, F	en
dc.contributor.author	Rascle, N	en
dc.contributor.author	Belibassakis, KA	en
dc.date.accessioned	2014-03-01T01:28:23Z
dc.date.available	2014-03-01T01:28:23Z
dc.date.issued	2008	en
dc.identifier.issn	1463-5003	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/18830
dc.subject	Drift	en
dc.subject	Generalized Lagrangian mean	en
dc.subject	Radiation stresses	en
dc.subject	Surface waves	en
dc.subject	Three dimensions	en
dc.subject	Wave-current coupling	en
dc.subject.classification	Meteorology & Atmospheric Sciences	en
dc.subject.classification	Oceanography	en
dc.subject.other	Approximation theory	en
dc.subject.other	Euler equations	en
dc.subject.other	Flow interactions	en
dc.subject.other	Mass transfer	en
dc.subject.other	Mathematical models	en
dc.subject.other	Ocean currents	en
dc.subject.other	Turbulence	en
dc.subject.other	Wave equations	en
dc.subject.other	Generalized Lagrangian mean theory	en
dc.subject.other	Radiation stresses	en
dc.subject.other	Wave-current coupling	en
dc.subject.other	Water waves	en
dc.subject.other	Eulerian analysis	en
dc.subject.other	Lagrangian analysis	en
dc.subject.other	mass transport	en
dc.subject.other	surface wave	en
dc.subject.other	turbulent flow	en
dc.subject.other	vertical profile	en
dc.subject.other	water depth	en
dc.subject.other	wave equation	en
dc.subject.other	wave field	en
dc.subject.other	wave force	en
dc.title	Explicit wave-averaged primitive equations using a generalized Lagrangian mean	en
heal.type	journalArticle	en
heal.identifier.primary	10.1016/j.ocemod.2007.07.001	en
heal.identifier.secondary	http://dx.doi.org/10.1016/j.ocemod.2007.07.001	en
heal.language	English	en
heal.publicationDate	2008	en
heal.abstract	The generalized Langrangian mean theory provides exact equations for general wave turbulence-mean flow interactions in three dimensions. For practical applications, these equations must be closed by specifying the wave forcing terms. Here an approximate closure is obtained under the hypotheses of small surface slope, weak horizontal gradients of the water depth and mean current, and weak curvature of the mean current profile. These assumptions yield analytical expressions for the mean momentum and pressure forcing terms that can be expressed in terms of the wave spectrum. A vertical change of coordinate is then applied to obtain glm2z-RANS equations with non-divergent mass transport in cartesian coordinates. To lowest order, agreement is found with Eulerian mean theories, and the present approximation provides an explicit extension of known wave-averaged equations to short-scale variations of the wave field, and vertically varying currents only limited to weak or localized profile curvatures. Further, the underlying exact equations provide a natural framework for extensions to finite wave amplitudes and any realistic situation. The accuracy of the approximations is discussed using comparisons with exact numerical solutions for linear waves over arbitrary bottom slopes, for which the equations are still exact when properly accounting for partial standing waves. For finite amplitude waves it is found that the approximate solutions are probably accurate for ocean mixed layer modelling and shoaling waves, provided that an adequate turbulent closure is designed. However, for surf zone applications the approximations are expected to give only qualitative results due to the large influence of wave nonlinearity on the vertical profiles of wave forcing terms. (c) 2007 Published by Elsevier Ltd.	en
heal.publisher	ELSEVIER SCI LTD	en
heal.journalName	Ocean Modelling	en
dc.identifier.doi	10.1016/j.ocemod.2007.07.001	en
dc.identifier.isi	ISI:000253019300003	en
dc.identifier.volume	20	en
dc.identifier.issue	1	en
dc.identifier.spage	35	en
dc.identifier.epage	60	en