This course covers fundamental aspects of fluid mechanics. It aims at developing an understanding of the physical mechanisms underlying fluid flow. It contains a review of the fundamental equations of Fluid Mechanics, an expansion of the methods of momentum analysis known from Thermofluids, and a detailed discussion of the powerful technique of Dimensional Analysis, which allows the systematic discovery of parameter sets that govern the characteristic features of a flow. These techniques will be used in engineering applications, such as the fluid mechanical treatment of turbomachines and devices for flow measurement. Special emphasis will be given to friction effects in fluid flows. Several examples of flows in which friction is important will be discussed, such as Couette flows, pipe flows and boundary layers. The final chapter of the course is an introduction to compressible flows.