I've seen that viscosity values in units of pressure (ie simply shear/elastic moduli times some dimensionless expression containing the Poisson ratio) get used for the Navier-Stokes equation when u is taken to be displacement rather than velocity. Nevertheless, I am still struggling to understand the relation between 'viscosities' in different units. How do I convert a volume viscosity whose value in Pa is known, to one in Pa s? Which time do I need to multiply with?ĮDIT: turned out that I misinterpreted cP as centipascal rather than centipoise (millipascal second), so there are some useful literature values after all. However, I am dealing with the time evolution of a system and thus am interested in velocity. the papers that I can find determining volume/bulk viscosity of various solids, liquids and gases experimentally all give values in Pa.the page points to the Lamé parameters lambda and mu, but on that page, these parameters are calculated with units of pressure (Pa) as Hooke's law in 3D is used which equates stress to strain, instead of strain rate.on the Wikipedia page Navier-Stokes equations, the stress tensor is given as a function of strain rate with lambda, mu and zeta having units of viscosity (Pa s).I am dealing with a problem where dynamic viscosity (in units Pa s) is known but volume viscosity is a material property that should be determined from literature, however I have trouble interpreting the units used in literature. Hi all, I have completely skipped fluid dynamics during my BSc and now I need to deal with it for my PhD to describe an elastic solid.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |