Measurement of the impuslive force generated by colapsing bubble close to a solid boundary

¹ Faculty of Mechanical Engineering, Technical University of Liberec, Studentskâ 2, 46117, Liberec 1, Czech Republic
milos.muller@tul.cz ; jiri.unger@tul.cz ; j.holata@seznam.cz
² Department of Thermodynamics, Institute of Thermomechanics, v.v.i., Academy of Sciences of the Czech Republic, DolejSkova 5, 18200 Praha, Czech Republic
zimap@it.cas.cz

Abstract

The article presents experimental results of the acoustical and optical study of cavitation bubble collapse close to a solid boundary in water. The bubble was generated by discharge of low-voltage capacitor into a couple of wires closing a simple circuit. Different distances from the solid wall and different maximum bubble radii were studied. The bubble radius was studied using time-resolved photography and by PVDF film sensor glued on the solid boundary. The illumination was provided by high-power led diode. Synchronization of the system was provided by pulse generator connected to an oscilloscope. The impact power of the bubble to the wall was estimated from the time-resolved photography of the bubble and from the PVDF film sensor signal. The PVDF film sensor calibration was performed by a pendulum test to estimate the impact force.