Inlet Turbulence Generation for Large Eddy Simulation: Applications to Fluid-Structure Interaction Problems
Abstract
The Large Eddy Simulation (LES) method has become practically a stan-
dard approach for the resolution of the Navier-Stokes (NS) equations
when the simulation of a turbulent flow is required. This is not only
due to the high accuracy and feasibility of LES but also to the
growing computational power and affordability that have taken place in
recent years. However, there are a number of issues that are still
being intensively stud- ied: mesh generation strategies, inlet and
boundary conditions, subgrid- scale (SGS) models, among others, in
order to extend the set of problems that can be solved by LES or to
reduce the computational cost involved. This scenario is further
complicated if the fluid-structure interaction (FSI) problem is added:
coupling algorithm and mesh moving strategy must be defined for every
problem. A particular field where the Computational Fluid Dynamics
(CFD) and FSI meet is in the road vehicle aerodynamics study. Until
recently (and even at present days) it has been preferred the
experimental rather than numerical simulation of such problems due to
the reliability gained by wind tunnels. Nevertheless, this
experimental tool has also shortcomings that can be corrected and even
strengths that can be improved by the use of numerical simulation. It
is the aim of this thesis to study the applicability of LES on road
vehicle aerodynamics including inlet turbulence generation and
fluid-structure in- teraction. In order to do that, a turbulent flow
over a simplified car model known as Ahmed's body is simulated. The
results obtained in this work lead to the conclusion that it is
possible to analyze the aerodynamic prop- erties of road vehicle
models in a complementary way with experimental and computational
tools.
dard approach for the resolution of the Navier-Stokes (NS) equations
when the simulation of a turbulent flow is required. This is not only
due to the high accuracy and feasibility of LES but also to the
growing computational power and affordability that have taken place in
recent years. However, there are a number of issues that are still
being intensively stud- ied: mesh generation strategies, inlet and
boundary conditions, subgrid- scale (SGS) models, among others, in
order to extend the set of problems that can be solved by LES or to
reduce the computational cost involved. This scenario is further
complicated if the fluid-structure interaction (FSI) problem is added:
coupling algorithm and mesh moving strategy must be defined for every
problem. A particular field where the Computational Fluid Dynamics
(CFD) and FSI meet is in the road vehicle aerodynamics study. Until
recently (and even at present days) it has been preferred the
experimental rather than numerical simulation of such problems due to
the reliability gained by wind tunnels. Nevertheless, this
experimental tool has also shortcomings that can be corrected and even
strengths that can be improved by the use of numerical simulation. It
is the aim of this thesis to study the applicability of LES on road
vehicle aerodynamics including inlet turbulence generation and
fluid-structure in- teraction. In order to do that, a turbulent flow
over a simplified car model known as Ahmed's body is simulated. The
results obtained in this work lead to the conclusion that it is
possible to analyze the aerodynamic prop- erties of road vehicle
models in a complementary way with experimental and computational
tools.