title: Lithotripter shock wave interaction with a bubble near various biomaterials.
abstract: Following previous work on the dynamics of an oscillating bubble near a bio-material (Ohl et al 2009 Phys. Med. Biol. 54 6313-36) and the interaction of a bubble with a shockwave (Klaseboer et al 2007 J. Fluid Mech. 593 33-56), the present work concerns the interaction of a gas bubble with a traveling shock wave (such as from a lithotripter) in the vicinity of bio-materials such as fat, skin, muscle, cornea, cartilage, and bone. The bubble is situated in water (to represent a water-like biofluid). The bubble collapses are not spherically symmetric, but tend to feature a high speed jet. A few simulations are performed and compared with available experimental observations from Sankin and Zhong (2006 Phys. Rev. E 74 046304). The collapses of cavitation bubbles (created by laser in the experiment) near an elastic membrane when hit by a lithotripter shock wave are correctly captured by the simulation. This is followed by a more systematic study of the effects involved concerning shockwave bubble biomaterial interactions. If a subsequent rarefaction wave hits the collapsed bubble, it will re-expand to a very large size straining the bio-materials nearby before collapsing once again. It is noted that, for hard bio-material like bone, reflection of the shock wave at the bone-water interface can affect the bubble dynamics. Also the initial size of the bubble has a significant effect. Large bubbles (∼1 mm) will split into smaller bubbles, while small bubbles collapse with a high speed jet in the travel direction of the shock wave. The numerical model offers a computationally efficient way of understanding the complex phenomena involving the interplay of a bubble, a shock wave, and a nearby bio-material.
authors.affiliation: Institute of High Performance Computing, 1 Fusionopolis Way #16-16 Connexis, 138632, Singapore.
authors.forename: S W
authors.initials: SW
authors.lastname: Ohl
authors.forename: E
authors.initials: E
authors.lastname: Klaseboer
authors.forename: A J
authors.initials: AJ
authors.lastname: Szeri
authors.forename: B C
authors.initials: BC
authors.lastname: Khoo
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D003198:Computer Simulation; D005740:Gases; D008096:Lithotripsy / Q000295:instrumentation / Q000379:methods*; D045423:Microbubbles; D044085:Microfluidics; D008962:Models, Theoretical; D009038:Motion; D011312:Pressure; D013010:Sonication
chemical_list: D001672:Biocompatible Materials; D005740:Gases