Modelagem do escoamento transcrítico sob regime permanente e transiente em canais
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2021-04-27
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Universidade Federal de Goiás
Resumo
The understanding of phenomena related to floods propagation along open
channels, especially in artificial urban ones, is becoming increasingly important to avoid
flooding and inundation as a result of intense precipitations. In this context, there is still
great difficulty in computational modeling certain hydraulic phenomena, such as hydraulic
jump, which may occur during a flood wave flow along channels under specific conditions
that generate changes in flow regimes.
Seeking a better understanding of this phenomenon, this work proposes the
development of computational tools that simulate, through physique and mathematical
equations, the propagation of flows that occur in the transition from supercritical to
subcritical regimes, the so-called transcritical flow. Two computational models were
developed for free-surface simulation. The first for the gradually varying permanent regime,
through the Standard Step Method, as proposed by Akan (2011). The second one for the
transient regime, based on solving the Saint-Venant equations in a hybrid way, where the
supercritical curve was defined by the Finite Difference Method (explicit resolution) as
proposed by Chaudhry (2007), and the subcritical curve was defined by the Preissmann
Method (implicit resolution). Comparisons among the conjugate heights of each flow curve
provided the flow transition point determination. These models were validated through
laboratory tests, performed in an experimental channel, simulating different scenarios of
transcritical flow, allowing the free-surface monitoring and measurement by means of a
graduated ruler (experiments in gradually varying permanent regime) and ultrasonic
sensors (transient regime).
In particular, we aim at computational modeling the hydraulic jump phenomenon, an
aproach of extreme importance and relevance for interventions in natural and artificial
channels in order to promote controlled energy dissipation, regulating and stabilizing the
propagation of floods and mitigating impacts downstream.
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CARVALHO, T. P. Modelagem do escoamento transcrítico sob regime permanente e transiente em canais. 2021. 94 f. Dissertação (Mestrado em Engenharia Ambiental e Sanitária) - Universidade Federal de Goiás, Goiânia, 2021.