Numerical study of the interaction between a pulsating coated microbubble and a rigid wall. II. Trapped pulsation

A coated microbubble approaching a solid substrate changes shape from prolate to oblate due to the balance of Bjerknes force and elasto-lubrication pressure. The bubble then undergoes trapped pulsations about an average static state corresponding to the Reissner response of a coated shell compressed by a rigid plate corrected for surface tension. The contact region length is inverse to shell stiffness, with thickness of tens of nanometers due to the balance of viscous shell and liquid stresses. The contact region flow is a Stokes layer generated in response to bubble translational and vibrational motion that are found to be in phase in our simulations, so steady streaming was not captured.