Abstract:
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[EN] The population tends to concentrate on big cities, leading to a problem of land for housing. High-rise buildings can host many people in little
ground, but these structures present different challenges, an important ...[+]
[EN] The population tends to concentrate on big cities, leading to a problem of land for housing. High-rise buildings can host many people in little
ground, but these structures present different challenges, an important factor for their design is the wind. The aerodynamic loads can cause strong
vibrations on the upper side, and the air may flow to the lower part and
cause disturbance to pedestrians. In this thesis different analysis of the flow
field around buildings are conducted. A simple structure is studied to test
different models used in Computational Fluid Dynamics (CFD) simulations
since experimental data is available. The numerical solution is obtained with
the steady Reynolds-Averaged Navier-Stokes (RANS) method and the unsteady approach (URANS), since this case is intrinsically steady both results
are analogous. About the turbulence, the standard k-epsilon model is chosen in a version improved by the comprehensive approach which addresses
two inconsistencies generated by the RANS approximations. For the good
implementation of this model, the Building Influence Area (BIA) concept is
integrated to apply the Non-Linear Eddy Viscosity (NLEV) model within
it. The improvements of this model will be shown by comparing its results
with traditional turbulence models as the k- and the SST k-ω. Once the
comprehensive approach is validated, it is implemented in another simple
geometry and later in a high-rise building in order to analyse the flow behaviour. The separation bubble at the top, the wake, the base vortex and
the corner streams are visualized. The comprehensive approach provides accurate results, but the simulation time is also higher. Moreover, the steady
simulations require a lower computational cost, however, an unsteady simulation is advisable for the skyscraper to study dynamic phenomenons that
could induce harmful vibrations and fatigue.
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[ES] En esta tesis se realizan diferentes análisis del flujo alrededor de edificios. Se estudia una estructura simple para probar diferentes modelos utilizados en simulaciones de Dinámica de Fluidos Computacional (CFD), ...[+]
[ES] En esta tesis se realizan diferentes análisis del flujo alrededor de edificios. Se estudia una estructura simple para probar diferentes modelos utilizados en simulaciones de Dinámica de Fluidos Computacional (CFD), ya que se dispone de datos experimentales. La solución numérica se obtiene tanto de forma estacionaria como transitoria. Sobre la turbulencia, se elige el modelo k-epsilon estándar en una versión mejorada por el ¿enfoque integral¿. Las mejoras de este modelo se mostrarán comparando sus resultados con modelos de turbulencia tradicionales. Una vez validado el enfoque integral, se implementa en otra geometría simple y luego en un edificio de gran altura para analizar el comportamiento del flujo.
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