Resumen de Finite volume computation and verification of fluid flow and het transfer phenomena in domains with moving boundaries and complex geometries
Problems where complex geometries or where moving boundaries exist arises in numerous scientific and engineering applications. Illustrative examples can be found in the thermal machinery field, such in reciprocating compressors, in internal combustion engines, or in air handling units. In the design and optimisation studies of theses systems, the detailed analysis of the heat and mass transfer phenomena becomes an essential issue. From the Computational Fluid Dynamics (CFD) point of view, a common characteristic to all these problems is the need to develop specific treatments from the standard CFD methodologies to deal with the geometry of the domain under study. The works conducted in this thesis tackle the modelization and the numerical methodology required for the fluid flow and heat transfer computation within this range of applications.
The flow computation in domains with moving boundaries is approached from the moving grid method. In this method, the governing equations are discretized over control volumes which change their geometry at every time-step. This non-Eulerian, or arbitrary Lagrangian-Eulerian (ALE), formulation introduces the necessity to satisfy the Space Conservation Law (SCL) together with the rest of governing equations. Failing in preserving this principle might lead to additional sources of error in the solutions, and, as it is demonstrated in this work, to introduce oscillatory behaviour in the convergence of the error. The studies conducted in this thesis are focused on the implementation of the moving grid method on Finite Volume (FV) computations, and on the analysis of the effects that parameters such as the mesh velocity, or the time and the SCL discretization, have on the accuracy and on the asymptotic or oscillatory convergence of both the space and time discretization errors. Test cases analysed include manufactured solutions, and the incompressible and compressible flow on different piston-cylinder configurations.
