Hi Drew, The velocity vector is the velocity magnitude multiplied by the normal. The normal is the gradient over the gradient magnitude so,

\vec{v} = \frac{\nabla \phi}{\nabla \phi \cdot \nabla \phi} \frac{\partial \phi}{\partial t} In Fipy you can get the gradient and gradient magnitude with the operations ".grad" and ".grad.mag" on cell variables. See, for example, https://www.ctcms.nist.gov/fipy/examples/phase/generated/examples.phase.impingement.mesh40x1.html, where a .grad.mag is used. Cheers, Daniel On Tue, Apr 3, 2018 at 4:55 PM, Drew Davidson <davidson...@gmail.com> wrote: > Hello, > > I was just looking at: > > Boettinger, W. J., J. A. Warren, C. Beckermann, and A. Karma. “Phase-Field > Simulation of Solidification.” Annual Review of Materials Research 32, no. 1 > (August 1, 2002): 163–94. > https://doi.org/10.1146/annurev.matsci.32.101901.155803. > > and maybe Equation 27 is the way to compute interface velocity in > examples.phase.anisotropy: > > v = -\frac{1}{\| \nabla \phi \|}\frac{\partial \phi}{\partial t} > > Then it remains to express the right hand side of that equation in the FiPy > language. It does look like this only gives the velocity magnitude rather > than the velocity vector. > > > On Tue, Apr 3, 2018 at 12:27 PM, Drew Davidson <davidson...@gmail.com> > wrote: >> >> Hello, >> >> In FiPy, how would one calculate the interface velocity at a given time >> step in examples.phase.anisotropy? >> >> At this time, I was mostly interested in the max and min of the magnitude >> of the interface velocity. >> >> Thanks > > > > _______________________________________________ > fipy mailing list > fipy@nist.gov > http://www.ctcms.nist.gov/fipy > [ NIST internal ONLY: https://email.nist.gov/mailman/listinfo/fipy ] > -- Daniel Wheeler _______________________________________________ fipy mailing list fipy@nist.gov http://www.ctcms.nist.gov/fipy [ NIST internal ONLY: https://email.nist.gov/mailman/listinfo/fipy ]