{ "id": "1911.06613", "version": "v1", "published": "2019-11-15T13:27:47.000Z", "updated": "2019-11-15T13:27:47.000Z", "title": "A geometric look at momentum flux and stress in fluid mechanics", "authors": [ "Andrew D. Gilbert", "Jacques Vanneste" ], "categories": [ "physics.flu-dyn" ], "abstract": "We develop a geometric formulation of fluid dynamics, valid on arbitrary Riemannian manifolds, that regards the momentum-flux and stress tensors as 1-form valued 2-forms, and their divergence as a covariant exterior derivative. We review the necessary tools of differential geometry and obtain the corresponding coordinate-free form of the equations of motion for a variety of inviscid fluid models -- compressible and incompressible Euler equations, Lagrangian-averaged Euler-$\\alpha$ equations, magnetohydrodynamics and shallow-water models -- using a variational derivation which automatically yields a symmetric momentum flux. We also consider dissipative effects and discuss the geometric form of the Navier--Stokes equations for viscous fluids and of the Oldroyd-B model for visco-elastic fluids.", "revisions": [ { "version": "v1", "updated": "2019-11-15T13:27:47.000Z" } ], "analyses": { "keywords": [ "fluid mechanics", "geometric look", "arbitrary riemannian manifolds", "symmetric momentum flux", "inviscid fluid models" ], "note": { "typesetting": "TeX", "pages": 0, "language": "en", "license": "arXiv", "status": "editable" } } }