The development of turbulent flows in the presence of walls occurs in both industrial and nature applications. This class of turbulent flows has great differences when compared to free turbulence. Incompressible flows in channels with shape modifications were studied in order to understand the effects of pressure gradient variations and curvature in the formation of coherent structures close to the wall. In addition, the effects of shape variation on flow anisotropy were also investigated in the Reynolds stress and in the turbulence cascade.
In the past decades, several discoveries were made in the theory of incompressible turbulent flows through experiments and numerical simulations. However, compressible turbulence has not been so extensively studied in comparison to the incompressible case. Smooth channels were studied in order to understand the effects of compressibility and Reynolds number on turbulence and the importance of the hydrodynamic, thermal and acoustic modes in the coherent turbulent structures.