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ICS-2 Talk: How is angular-momentum conservation lost in discretization of Navier-Stokes equation?

Hiroshi Noguchi
Institute for Solid State Physics, University of Tokyo


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19 Nov 2018 14:00
venue
Gebäude 04.16, Raum 2001

Abstract:

Although the Navier-Stokes equation (NSE) is derived under angular-momentum conservation (AMC), numerical simulation methods often lack it. Here, we reveal that AMC violations result from implementation of the degenerated viscous terms of NSE.

To maintain AMC, these degenerated terms must be separately integrated in accordance with their stress origins. As observed in particlebased hydrodynamics methods, the violation causes artificial rotations in multi-component fluids with different viscosities. We also clarify that the condition for constant fluid rotation as a rigid body in a container rotating at a constant speed is not the AMC of the stresses, but the invariance of the viscous forces under a global rotation.

To confirm our theory, we simulated the circular laminar flows of single- and binary-component fluids using two-dimensional Lagrangian finite volume methods. The results show excellent agreement with the analytical predictions for fluids with and without AMC.

Contact

PD Dr. Jens Elgeti
Phone: +49 2461 61-9382
Fax: +49 2461 61-3180
email: j.elgeti@fz-juelich.de

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