Thesis SIMULACIÓN A GRAN ESCALA DEL IMPACTO DE LAS OLAS EN EL BORDE COSTERO
Date
2016-10
Authors
OSORIO CASTRO, RENATO AYRTON
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Abstract
Se realizaron simulaciones numéricas para olas de tipo spilling y plunging bajo un modelo numérico tipo LES, que separa el fluido en dos escalas: una escala grande para la cual se resuelven las ecuaciones de Navier-Stokes, y una escala pequeña para la cual se aplicó el modelo de sub-grid de Smagorisky. Se simula la superficie libre a través del método VOF (“Volume of Fluid”). Se midió la elevación de la superficie de agua, la amplitud de las olas, su velocidad promediada, energía cinética turbulenta y esfuerzos de corte en el fondo marino. Se evaluó la precisión del método comparando los resultados de la simulación con los resultados experimentales del experimento de laboratorio de Ting & Kirby (1994). Se obtuvieron resultados satisfactorios en el punto de rotura de la ola y su estructura hidrodinámica, sin embargo la simulación no logró predecir con precisión la altura de la ola al momento de su rotura ni sus niveles de turbulencia. Han sido caracterizadas las diferencias de comportamiento hidrodinámico entre una ola tipo spilling y una tipo plunging. Finalmente se intentó establecer la forma en que se modifica la morfología costera midiendo los esfuerzos de corte en el fondo marino, sin embargo, bajo las condiciones elegidas para la simulación no existe movimiento de sedimentos.
Numerical simulations were performed for spilling and plunging waves using a LES model, in which the fluid is separated into two scales: a large one in which Navier Stokes equations are solved, and a small one in which a Smagorisnky sub-grid scale model is used. The free surface is simulated with the VOF (Volume of fluid) method. The elevation of the free surface of water was measured, along with the amplitude of the waves, the mean velocity, kinetic turbulent energy and shear stresses in the sea bottom. The precision of the method was evaluated, in comparison with experimental measures of the Ting & Kirby (1994) lab experiment. Satisfactory results were obtained in the breaking point of the wave and his hydrodynamic structure, nevertheless, the simulation failed to predict either the height of the wave at the time of breaking or its turbulence levels. The difference of hydrodynamic behavior between spilling and plunging waves has been characterized. Finally, there was an attempt to establish the way in which the coastal morphology is modified, by measuring the shear stresses in the sea bottom, however, under the conditions simulated, there is no sediment movement.
Numerical simulations were performed for spilling and plunging waves using a LES model, in which the fluid is separated into two scales: a large one in which Navier Stokes equations are solved, and a small one in which a Smagorisnky sub-grid scale model is used. The free surface is simulated with the VOF (Volume of fluid) method. The elevation of the free surface of water was measured, along with the amplitude of the waves, the mean velocity, kinetic turbulent energy and shear stresses in the sea bottom. The precision of the method was evaluated, in comparison with experimental measures of the Ting & Kirby (1994) lab experiment. Satisfactory results were obtained in the breaking point of the wave and his hydrodynamic structure, nevertheless, the simulation failed to predict either the height of the wave at the time of breaking or its turbulence levels. The difference of hydrodynamic behavior between spilling and plunging waves has been characterized. Finally, there was an attempt to establish the way in which the coastal morphology is modified, by measuring the shear stresses in the sea bottom, however, under the conditions simulated, there is no sediment movement.
Description
Catalogado desde la version PDF de la tesis.
Keywords
LES , OLAS , SIMULACION