Modelagem do escoamento transcrítico sob regime permanente e transiente em canais

• Autor(a) principal: Carvalho, Thiago Pires de
• Data de Publicação: 2021
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFG
• dARK ID: ark:/38995/0013000005hwq
• Texto Completo: http://repositorio.bc.ufg.br/tede/handle/tede/11448
• topic: Escoamento transcrítico; Ressalto hidráulico; Modelagem hidráulica; Transcritical flow; Hydraulic jump; Hydraulic model; ENGENHARIAS::ENGENHARIA SANITARIA::RECURSOS HIDRICOS

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.