Experimental study to produce flow stream of microbubbles by forming time variation of two focal sound fields with opposite phase

We have reported path selection of microbubbles as a high density delivery method in flow by acoustic radiation force. However, it was impossible to change the sound field shape according to the movement of the microbubbles. In this study, forming the sound field with time variation using 2D ultrasound array transducer, we observed behavior of microbubbles in the thin channel of thickness 2mm. By forming two focal sound fields with opposite phases symmetrical in direction of flow and moving them towards the area C, we were able to form flow stream of microbubbles. From the result, it is suggested that higher density microbubbles can be delivered than previous methods.