Modeling the observations of in vivo bubble formation with hydrophobic crevices

In vivo hydrophobic crevices from which bubbles emerge upon decompression are hypothesized to account for experimental observations of bubble formation in decompressed shrimp. The conical crevice model can be used to explain the sharp increase in the number of bubbles observed in shrimp for decompression ratios greater than 4:1. In accordance with the observed attenuating effects of pressure pretreatment on bubble formation in shrimp, the model can also be used to explain: the evolution of the gas nuclei to smaller stable sizes during compression; the return of the nuclei to their original stable configurations when the overpressure is removed; and the requirement for greater decompressions to cause emergence of bubbles from the nuclei as the magnitude and period of pressure pretreatment are increased. A new crevice geometry with elliptically shaped walls is introduced which reduces the height of the crevice needed for bubble emergence and relaxes the constraints for the stability of gas nuclei. This new geometry reduces the height of crevices required for the prediction of bubble emergence an order of magnitude when compared to the conical crevice, and satisfies the hydrophobic crevice condition as long as the crevice surface has a contact angle greater than 90 degrees.