Ski-snow friction is a highly dynamic, complex, and still poorly understood process (Colbeck, 1992; Moldestad, 1999; Bäurle, 2008). Our current idea of sliding friction is the following: As the ski glides along, there is first mutual deformation of the ski base and the snow surface, and the building of contacts between the two media. Energy is then released by dry friction, leading to meltwater formation and lubricated friction at the contact spots. As a consequence, friction is reduced as compared to a purely dry friction situation. The melting process may eventually cause the formation of capillary bridges between the ski base and the snow, leading to a rise in friction. As the ski glides along the snow surface, there is probably continuous formation and breaking up of the contact spots. It is probable that friction is minimal when the contact area between ski and snow is minimal and when there is just enough water formed to have lubricated friction at the contact spots. Evidence for an optimal friction situation was found by various authors (e.g., Buhl, Fauve, & Rhyner, 2001) who investigated the dependency of gliding resistance on snow temperature. These authors found a minimum at around -3°C and a significant increase of friction both toward lower temperatures and toward 0°C. The aim of the current work was to build up a more thorough understanding of the basic underlying processes in ski-snow friction and to use this knowledge to optimize ski base structures as a function of the snow properties. The investigations focused on the formation of contacts and the lubricating water between ski and snow. The study was restricted to hard snow conditions.
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