Effect of pulsed ultrasonic field on the filling of a capillary with a liquid

The filling of capillaries with liquids of various viscosity in the ultrasonic field is experimentally investigated. It is shown that the breakage of the meniscus and the fast intense dissolution of the gas that filled the capillary occur at the threshold switching-on of the ultrasonic field in low-viscosity liquids. This causes the residual (after switching-off of the ultrasound) filling of the capillaries with a low-viscosity liquid. It is established that the residual filling of capillaries is observed only with the pressure amplitudes P-m exceeding some critical value; the residual filling increases with P-m and disappears as cavitation is induced below the capillary end. It is shown that pulsed regime is optimal for the ultrasonication.