Purely elastic linear instabilities in parallel shear flows with free-slip boundary conditions
| Autor: | Moritz Linkmann, Alexander Morozov, Martin Lellep, Bruno Eckhardt |
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| Rok vydání: | 2021 |
| Předmět: |
Physics
Body force Plane (geometry) Mechanical Engineering Constitutive equation Fluid Dynamics (physics.flu-dyn) Classical Physics (physics.class-ph) FOS: Physical sciences Physics - Fluid Dynamics Physics - Classical Physics Slip (materials science) Mechanics Condensed Matter Physics Hagen–Poiseuille equation Viscoelasticity Physics::Geophysics Shear (sheet metal) Physics::Fluid Dynamics Mechanics of Materials Boundary value problem |
| DOI: | 10.48550/arxiv.2108.03126 |
| Popis: | We perform a linear stability analysis of viscoelastic plane Couette and plane Poiseuille flows with free-slip boundary conditions. The fluid is described by the Oldroyd-B constitutive model, and the flows are driven by a suitable body force. We find that both types of flow become linearly unstable, and we characterise the spatial structure of the unstable modes. By performing a boundary condition homotopy from the free-slip to no-slip boundaries, we demonstrate that the unstable modes are directly related to the least stable modes of the no-slip problem, destabilised under the free-slip situation. We discuss how our observations can be used to study recently discovered purely elastic turbulence in parallel shear flows. Comment: 10 pages, 7 figures |
| Databáze: | OpenAIRE |
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