Simulações numéricas de correntes gravitacionais com elevado número de Reynolds

• Autor(a) principal: Frantz, Ricardo André Schuh
• Data de Publicação: 2018
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da PUC_RS
• Texto Completo: http://tede2.pucrs.br/tede2/handle/tede/8127
• topic: Simulação de Grandes Escalas; Modelagem de Escala de Submalha; Dissipação Numérica; Viscosidade Turbulenta Espectral; Correntes de Gravidade; Large Eddy Simulation; Subgrid-scale Modelling; Numerical Dissipation; Spectral Vanishing Viscosity; Gravity Currents; ENGENHARIAS

This work investigates the method of large-eddy simulation (LES) in the context of gravity currents, which is found necessary since it allows a substantial increase in the order of magnitude of the characteristic Reynolds number used in numerical simulations, approaching them with natural scales, in addition to significantly reducing the computational cost. The implicit large eddy simulation (ILES) methodology, based on the spectral vanishing viscosity model, is unprecedentedly employed in the context of gravity currents, is compared against with explicit methods such as the static and dynamic Smagorisnky. The evaluation of the models is performed based on statistics from a direct numerical simulation (DNS). Results demonstrate that the first model based purely on numerical dissipation, introduced by means of the second order derivative, generates better correlations with the direct simulation. Finally, experimental cases of the literature, in different flow configurations, are reproduced numerically showing good agreement in terms of the front position evolution.