Abstract : The generic term "von Karman flows" designates the class of flows induces by the rotation of two coaxial disks facing each other. We have collected in the first part of this dissertation a variety of experimental results pertaining to the characterization of the large-scale fluctuations of the flow generated in a cylindrical vessel of nearly unitary aspect ratio. We show that in certain circumstances the overall structure of the flow can undergo a "global bifurcation", or have an "intermittent behaviour". Independently, we report on a relationship linking quantitatively simple flow statistics to the torque exerted on the flow by the driving mechanism. We then present a brief survey of the influence of global rotation on the flow. The second part of this dissertation gathers numerical and experimental results related to the magneto-hydrodynamical properties of the flow. A particular emphasis is set on the study of its ability to generate a magnetic field through the "dynamo effect". The experimental results have been obtained for large values of the magnetic Reynolds number in a dedicated setup using liquid sodium, the "VKS" apparatus.