theta step1((T-T_m)/dT) Fraction of liquid phase f (1-theta)^2/(theta^3+epsilon) Volume force prefactor Fr -f*A_mush*u Volume force density, r-component Fz -f*A_mush*(w-v_cast) Volume force density, z-component D d(theta,T) Temperature dependence, latent heat Cp1 380[J/(kg*K)]+(dH/T_m)*theta Heat capacity + latent heat contribution