Publication Date:
2022-05-26
Description:
Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution, February, 1993
Description:
In this thesis, mechanisms which control morphodynamics of shallow tidal embayments are investigated analytically. In the
process of exploring these mechanisms (specifically asymmetries in bottom stress, τ), basis momentum and mass balances which
govern flow in these systems are clarified. Temporal asymmetries in τ are investigated via a new perturbation scheme which
quantifies nonlinear processes and combines geometric controls on asymmetry into a single non-dimensional parameter.
Implications of spatial asymmetries in τ are investigated though stability criteria based on a uniform distribution of τ.
Morphologic observations of both tidal channels and intertidal flats are consistent with a unifonn distribution of τ at equilibrium.
Investigation of morphodynamic mechanisms leads to scalings of momentum and continuity which diverge from classical models.
Scalings for prismatic channels with strong tidal asymmetries indicate friction often dominates acceleration in the momentum
equation. The resulting "zero-inertia" balance gives a time-varing diffusion equation which requires along-channel amplitude to
decay. Uniform τ justifies a new scaling of continuity for exponentially-shaped channels. In such channels, along-channel
gradients in tidal velocity are small and are often dominated by gradients in cross-sectional area. The resulting first-order wave
equation allows only constant amplitude, forward propagating waveforms which are independent of channel length.
Description:
Funding was provided by the Offce of Naval Research through the American Society for Engineering
Education and the National Science Foundation under grant OCE91-02429.
Keywords:
Tidal channels
;
Hydrodynamics
;
Tidal flats
Repository Name:
Woods Hole Open Access Server
Type:
Technical Report
,
Thesis
Format:
8922475 bytes
Format:
application/pdf
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