Tesis doctoral de Roland Garnier
This thesis performs a nonlinear stability study of the surf zone morphodynamics of sandy beaches. To this end the morfo55 model based on a wave and depth averaged nonlinear shallow water equations solver with wave driver, sediment transport and bed updating is presented. It is first applied to complex longitudinally non-uniform beaches in order to test different model formulations. Second, it is applied to study the generation of surf zone rhythmic features on alongshore uniform beaches. Shore-attached transverse or oblique bars, crescentic bars and ridge and runnel systems are well known examples of such features. The hypothesis that they emerge by self-organisation of the coupling between topography, waves and currents is here tested. In absence of shore-parallel bars, the initial formation of transverse and oblique bars had been shown by previous modelling studies of linear stability analysis but is now extended to the finite amplitude regime. In most of barred beaches, crescentic bars and ridge and runnel systems appear. Conceptual models based on field observations suggest that ridges and runnels could emerge by the deformation of the alongshore intertidal bar intercepted by crescentic bars. Up to now, only the formation of crescentic bars had numerically succeeded with linear and non linear models. This study shows that a dynamical equilibrium state of each of these rhythmic bar systems may be described with a numerical model. General results are in qualitative agreement with the bar systems observed in nature. A physical explanation for their formation, their evolution and the saturation of their growth is given.
Datos académicos de la tesis doctoral «Nonlinear modelling of surf zone morphodynamical instabilities«
- Título de la tesis: Nonlinear modelling of surf zone morphodynamical instabilities
- Autor: Roland Garnier
- Universidad: Politécnica de catalunya
- Fecha de lectura de la tesis: 21/03/2007
Dirección y tribunal
- Director de la tesis
- Alberto Falqués Serra
- Tribunal
- Presidente del tribunal: huib De swart
- thierry Garlan (vocal)
- philippe Bonneton (vocal)
- yolanda Ciriano nogales (vocal)