Numerical investigation of two-microbubble collapse and cell deformation in an ultrasonic field

•A numerical investigation of two-microbubble interaction near a deformable cell in an ultrasonic field is presented.•The interactions between the two collapsing bubbles produce a strong liquid jet and cause significant cell deformation compared to single-bubble collapse.•A variety of bubble interactions and associated cell deformation are demonstrated depending on the bubble-bubble distances and size ratios.•The optimal bubble-bubble distance and size ratio for cell deformation are presented via contour maps for various acoustic pressure amplitudes and frequencies. Two-microbubble collapse near a spherical cell in an ultrasonic field is numerically analyzed by extending a level-set method for compressible multiphase flows with bubble and cell multiple interfaces. Computations performed with different bubble-bubble distances and size ratios demonstrate various bubble-bubble interactions, such as bubble coalescence, bubble repulsion and attraction, jet penetration into the bubble, and jet collision. The interactions between collapsing bubbles are found to produce strong liquid jet formation and result in significant cell deformation compared to single-bubble collapse. The optimal bubble-bubble distance and size ratio for cell deformation are presented via contour maps based on extensive computations. The influences of the ultrasonic amplitude and frequency on cell deformation are further investigated.