In the MPPIC tutorials, the default values for MPPIC_COEFF_EN1 and MPPIC_COEF_EN2 are 0.5. Are these coefficients specific to the solids phase? Are they related to the particle’s restitution coefficient at all?
You appear to be using a older version of the code because MPPIC_COEFF_EN2 was removed as an input parameter. Earlier MFIX versions that use this input are not supported.
The current tie in for MPPIC_COEFF_EN1 relates to how the solids stress model is applied, and it really shouldn’t be thought of as a material property. This input provides a way to fine-tune the solids stress model and it is strongly recommended that you keep the default values.