The zero equation turbulence model calculates the kinematic eddy viscosity using the formula.
G = (
2 * u.diff(x) ** 2
+ 2 * v.diff(y) ** 2
+ 2 * w.diff(z) ** 2
+ (u.diff(y) + v.diff(x)) ** 2
+ (u.diff(z) + w.diff(x)) ** 2
+ (v.diff(z) + w.diff(y)) ** 2
)
nu_t = rho * mixing_length**2 * sqrt(G)
The python script refers to this article as the source of the equation. The article gives a formula, for calculating dynamic eddy viscosity mu_t. The implementation uses the exact same formula but gets nu_t as the result. I belive that the correct equation would be:
nu_t = mixing_length**2 * sqrt(G)
since
nu = mu/rho
I may have misunderstood something about the relationship between dynamic and kinematic eddy viscosity, but this seems like an error.