P1F-1 A Novel Method of Micro Bubble Trapping by Bubble Nonlinear Oscillation

A novel method of micro bubble trapping by nonlinear bubble oscillation under ultrasonic wave radiation is proposed. Two ultrasonic waves, which have harmonic relation in frequencies, are used in order to produce the Bjerknes force to the bubble. First ultrasonic wave is pumping wave, which has relative high sound pressure. This wave is used for generating nonlinear oscillation of bubble. Second wave is control wave, whose frequency is set to a harmonic frequency of the pumping wave. Two waves are crossed at the area where the bubbles are trapped. The pressure gradient of the control wave in conjunction with a harmonic component of bubble nonlinear oscillation produces the Bjerknes force to the bubble, making multiple bubble traps with narrow separation of wavelength of the control wave. Basic experiments are carried out using an ultrasonic contrast agent bubble