Yield-stress fluids in porous media: a comparison of viscoplastic and elastoviscoplastic flows
| Autor: | Francesco De Vita, Luca Brandt, Outi Tammisola, Daulet Izbassarov, Emad Chaparian |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
Pressure drop
Materials science Viscoplasticity Continuous flow Mechanical Engineering Porous media 02 engineering and technology Mechanics Condensed Matter Physics 01 natural sciences Yield-stress fluid Stress (mechanics) 020303 mechanical engineering & transports 0203 mechanical engineering Flow (mathematics) Mechanics of Materials 0103 physical sciences Viscoplastic fluid Yield limit Porous medium 010301 acoustics Elastoviscoplastic fluid Pressure gradient Recent Advances in Modeling and Simulations of Multiphase Flows |
| Zdroj: | Meccanica |
| ISSN: | 0025-6455 |
| Popis: | A numerical and theoretical study of yield-stress fluid flows in two types of model porous media is presented. We focus on viscoplastic and elastoviscoplastic flows to reveal some differences and similarities between these two classes of flows. Small elastic effects increase the pressure drop and also the size of unyielded regions in the flow which is the consequence of different stress solutions compare to viscoplastic flows. Yet, the velocity fields in the viscoplastic and elastoviscoplastic flows are comparable for small elastic effects. By increasing the yield stress, the difference in the pressure drops between the two classes of flows becomes smaller and smaller for both considered geometries. When the elastic effects increase, the elastoviscoplastic flow becomes time-dependent and some oscillations in the flow can be observed. Focusing on the regime of very large yield stress effects in the viscoplastic flow, we address in detail the interesting limit of ‘flow/no flow’: yield-stress fluids can resist small imposed pressure gradients and remain quiescent. The critical pressure gradient which should be exceeded to guarantee a continuous flow in the porous media will be reported. Finally, we propose a theoretical framework for studying the ‘yield limit’ in the porous media. |
| Databáze: | OpenAIRE |
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