  Two benchmark problems for quantitative assessment of anisotropic curvature
driving force in phase field method were developed and introduced. Both
benchmarks contained an anisotropically shrinking grain in homogeneous matrix.
The first benchmark was a shrinking Wulff shape and in the second, such
inclination dependence of the kinetic coefficient was added so that the
shrinkage was isotropic. In both cases the match to the expected shape was
quantified by means of Hausdorff distance and the shrinkage rate was
analytically expressed. Three different ways of interface energy anisotropy
inclusion in a multi-phase field model were compared. Because their performance
was comparable, they were tested in an additional benchmark problem, which
concerned direct measurement of equilibrium triple junction angles. Based on
this benchmark, only one of the three strategies to include anisotropy was
reliable in strongly anisotropic systems.
