User Defines power-law viscosity model

When I run this I get an immediate error:

Program received signal SIGFPE: Floating-point exception - erroneous arithmetic operation.

Backtrace for this error:
#0  0x7fd6b00e66b0 in ???
#1  0x7fd6b00e5865 in ???
#2  0x7fd6fcc1931f in ???
#3  0x7fd6b0428c3e in usr_prop_mug_
	at /tmp/MN/usr_properties.f:235

This is an issue with your code, not with MFiX.

Line 235 of usr_properties.f looks like this:

                  Mu_sv =((2.d0+ALPHA)/3.d0)*((Mu_star/(Eta*(2.d0-Eta)*&
                     G_0(IJK,M,M)))*(ONE+1.6d0*Eta*SUM_EpsGo)&
                     *(ONE+1.6d0*Eta*(3d0*Eta-2d0)*&
                     SUM_EpsGo)+(0.6d0*Mu_bv*Eta))

There’s a lot of calculation going on there, and somewhere you are dividing by zero.

I suggest breaking up the complex calculation into several sub-calculations, and checking all denominators before doing any division, as described in this forum posting