Galerkin Least-Squares Stabilization Operators for the Navier-Stokes Equations: A Unified Approach

In this dissertation we attempt to approach fluid mechanics problems from a unified point of view and to combine techniques developed originally for compressible or incompressible flows into a more general framework. In order to study the viability of a unified approach, it is necessary to choose a starting formulation, therefore the choice of variables in the governing equations is crucial. For example, conservative variables are not suitable for a unified formulation because they result in a singular limit for incompressible flows. When entropy or pressure primitive variables are used, then the incompressible limit of the Navier-Stokes equations is well-defined, hence they are a suitable choice for obtaining a unified formulation. These two sets of variables are investigated in detail.