Effect of flow acceleration on mass or heat transfer at the surface of a spherical bubble

Numerical results concerning mass or hear transfer on a spherical bubble embedded in axisymmetrical accelerated flows are presented. The Reynolds number is varied between 0.1 and 500. Two different situations are considered namely an unsteady flow with a constant acceleration, and a pure straining pow where the homogeneous strain induces a spatial acceleration In the latter case, the acceleration is seen to have little effect on the transfer In contrast in the unsteady case, computations reveal that dramatic history effects may happen. A comparison of characteristic times allows us to explain the various evolutions shown by the computations. These numerical results are confirmed by analytical solutions obtained in the corresponding situations by assuming a potential flow. (C) Academie des sciences/Elsevier Paris.