in polymer science
symbol: $f$; unit: $\pu{kg s-1}$
symbol: $f$; unit: $\pu{kg s-1}$
synonym: frictional coefficient (in polymer science)
https://doi.org/10.1351/goldbook.12246
Frictional force, \(F\), per unit velocity, \(u\), experienced by an isolated spherical body moving unidirectionally in a viscous isotropic fluid, i.e., \(F = fu\).
Notes:
- More generally, \(\boldsymbol{f}\) is defined as the tensor that correlates the vectorial frictional force, \(\boldsymbol{F}\), on a body in a viscous fluid and the vectorial velocity, \(\boldsymbol{u}\) , with \(\boldsymbol{F} = \boldsymbol{f}\boldsymbol{u}\). However, the more general definition is not needed in polymer science as experimental determinations of the translational frictional coefficient all employ situations in which \(\boldsymbol{F}\) and \(\boldsymbol{u}\) are collinear and \(F = fu\).
- \(f\) is related to the translational diffusion coefficient, \(D\), of an isolated body by the Einstein equation \(D = kT/f\), where \(k\) is the Boltzmann constant and \(T\) the thermodynamic temperature.