Measurement of the friction law between a wet finger and a glass oscillator: Application to the Cristal Baschet

The cristal Baschet is a musical instrument created during the 50's. The produced sound results from vibrations induced by friction between wet fingers and glass rods. Each glass rod is connected to an assembly of threaded shaft and mass, whose dynamic properties determine the frequency of self-oscillation. In this work, an experimental method is proposed to identify the friction law between a wet finger and the glass, with the aim of achieving more accurate modelling of the sound production mechanism. The normal and tangential forces between the finger and the glass rod are identified by solving an inverse problem, from in-situ measurements using accelerometers and a high speed camera. Experimental identification of the friction law therefore makes it possible to estimate its variability with parameters such as the quantity of water or the diversity of fingers.