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Wind-forced linear and nonlinear Kelvin waves along an irregular coastline

Published online by Cambridge University Press:  12 April 2006

Allan J. Clarke
Allan J. Clarke
Affiliation:
Department of Earth and Planetary Sciences, Massachusetts Institute of Technology, Cambridge
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Abstract

Using a normal and tangential co-ordinate approach, a perturbation theory is developed for wind-forced linear and nonlinear Kelvin waves propagating along an irregular coastline. The theory is valid for coastline curvatures which are non-dimensionally small, the curvature being non-dimensionalized with respect to the reciprocal of the boundary-layer trapping scale, i.e. the reciprocal of the radius of deformation. According to linear theory, the main effect of a coastline of small curvature is to cause a phase-speed change in the wave (from – c to – c(1 – ½k(s)), where k(s) is the non-dimensional curvature a distance s along the coast from the origin) and to make the offshore Ekman transport change more rapidly along the coast, the latter effect implying a more ‘wavelike’ ocean or lake response. Two discernible nonlinear effects were found to be an increase (decrease) in the linear-solution longshore gradients in regions of positive (negative) isopycnal displacement and a tendency for increased (decreased) isopyncal displacement at capes (bays).

Type
Research Article
Information
Journal of Fluid Mechanics , Volume 83 , Issue 2 , 22 November 1977 , pp. 337 - 348
Copyright
© 1977 Cambridge University Press

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