partial values are accumulated into eta_r while executing a for loop. Unfortunately eta_r is uninitialized, so according to Section 12.4.4 this model seems to be invalid.
I would recommend to add an initialization statement eta_r :=0 before entering the for loop.
In this line
https://github.com/thorade/HelmholtzMedia/blob/7b867a59b0556b443b2ad463bf3d21d9e1d5537d/HelmholtzMedia/Interfaces/PartialHelmholtzMedium/Transport/dynamicViscosity_residual.mo#L113
partial values are accumulated into
eta_rwhile executing a for loop. Unfortunatelyeta_ris uninitialized, so according to Section 12.4.4 this model seems to be invalid.I would recommend to add an initialization statement
eta_r :=0before entering the for loop.