Pipe flow of shear-thinning fluids
| Autor: | Chérif Nouar, Mathieu Jenny, Santiago Nicolas López-Carranza |
|---|---|
| Rok vydání: | 2012 |
| Předmět: |
Marketing
Shear thinning Plug flow Strategy and Management Carreau fluid Reynolds number Mechanics Non-Newtonian fluid Open-channel flow Pipe flow Condensed Matter::Soft Condensed Matter Physics::Fluid Dynamics symbols.namesake Classical mechanics Flow (mathematics) Media Technology symbols General Materials Science Mathematics |
| Zdroj: | Comptes Rendus Mécanique. 340:602-618 |
| ISSN: | 1631-0721 |
| DOI: | 10.1016/j.crme.2012.05.002 |
| Popis: | Pipe flow of purely viscous shear-thinning fluids is studied using numerical simulations. The rheological behavior is described by the Carreau model. The flow field is decomposed as a base flow and a disturbance. The perturbation equations are then solved using a pseudo-spectral Petrov–Galerkin method. The time marching uses a fourth-order Adams–Bashforth scheme. In the case of an infinitesimal perturbation, a three-dimensional linear stability analysis is performed based on modal and non-modal approaches. It is shown that pipe flow of shear-thinning fluids is linearly stable and that for the range of rheological parameters considered, streamwise-independent vortices are optimally amplified. Nonlinear computations are done for finite amplitude two-dimensional disturbances, which consist of one pair of longitudinal rolls. The numerical results highlight a strong modification of the viscosity profile associated with the flow reorganization. For a given wall Reynolds number, shear-thinning reduces the energy gain of the perturbation. This is due to a reduction of the exchange energy between the base flow and the perturbation. Besides this, viscous dissipation decreases with increasing shear-thinning effects. |
| Databáze: | OpenAIRE |
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