In this chapter an introduction to the topic of turbulent flows is presented, according to the following sections: Sect. 1.1, an approach to dynamical systems, chaos and turbulence; Sect. 1.2, the characterization of turbulent flows; Sect. 1.3, a physical model for the transformation of energy via viscous process; Sect. 1.4 manifestation of turbulence; and, concluding with Sect. 1.5, exercises for the review and consolidation of the concepts presented in this chapter.