Abstract
The mass transport into a fluid bounded by stationary rigid walls in the limit of large Péclet number, Pe, is examined analytically. Two model systems are considered in detail: a stationary cavity and a model involving two concentric rotating cylinders. A macroscopic gradient is imposed between the top and bottom surfaces. It is demonstrated that mass transport into the fluid is enhanced owing to a recirculation zone which is connected to the solid boundary through a boundary layer of thickness O(Pe−1/3) in which cross-stream molecular diffusion is balanced by convection. The associated enhancement is large and scales as Pe1/3. Our asymptotic analysis is found to be in good agreement with numerical solutions of the full transport equation.
Original language | English |
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Pages (from-to) | 45-64 |
Number of pages | 20 |
Journal | Journal of Engineering Mathematics |
Volume | 42 |
DOIs | |
Publication status | Published - Jan 2002 |
Keywords
- mass-transport enhancement
- diffusion
- effective diffusivity
- Recirculation zone