Publication Date:
2018-01-29
Description:
Oceanic internal solitary waves are typically generated by barotropic tidal flow over localised topography. Wave generation can be characterised by the Froude number , where is the tidal flow amplitude and is the intrinsic linear long wave phase speed, that is the speed in the absence of the tidal current. For steady tidal flow in the resonant regime, 〈![CDATA[ [STIX]x1D6E5-m〈F-1, a theory based on the forced Korteweg-de Vries equation shows that upstream and downstream propagating undular bores are produced. The bandwidth limits depend on the height (or depth) of the topographic forcing term, which can be either positive or negative depending on whether the topography is equivalent to a hole or a sill. Here the wave generation process is studied numerically using a forced Korteweg-de Vries equation model with time-dependent Froude number, , representative of realistic tidal flow. The response depends on , where is the maximum of over half of a tidal cycle. When 〈![CDATA[ [STIX]x1D6E5-max the flow is always subcritical and internal solitary waves appear after release of the downstream disturbance. When 〈![CDATA[ [STIX]x1D6E5-m the tidal flow goes through the resonant regime twice, producing undular bores with each passage. The numerical simulations are for both symmetrical topography, and for asymmetric topography representative of Stellwagen Bank and Knight Inlet. © 2018 Cambridge University PressÂ.
Print ISSN:
0022-1120
Electronic ISSN:
1469-7645
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
,
Physics
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