Hello All -

I am trying to simply define the diffusivity properties of 5 different species for two different zones. I have decided using if loops is the most efficient. Everything appears to be in order, and the UDF hooks to fluent just fine, but when I attempt to begin iterating, I get "Floating Point Error: invalid number." I am not sure if fluent is even recognizing the coefficients I am putting in. Please Help!!! Cheers

#include "udf.h" DEFINE_DIFFUSIVITY(protondiff,c,t,i) {

real D; int zone_ID = THREAD_ID(t);

if (i == 1){

if (zone_ID==2)

{D = 2.03e-15;}

if (zone_ID==3)

{D =2.03e-15;} return D;}

if (i == 2){

if (zone_ID==2)

{D = 8.91e-10;}

if (zone_ID==3)

{D = 9.90e-10;} return D;}

if (i == 3){

if (zone_ID==2)

{D = 1.9285e-11;}

if (zone_ID==3)

{D = 2.03e-11;} return D;}

if (i == 4){

if (zone_ID==2)

{D = 4.275e-11;}

if (zone_ID==3)

{D = 4.5e-11;} return D;}

if (i == 5){

if (zone_ID==2)

{D =2e-15;}

if (zone_ID==3)

{D = 2e-15;} return D;} }

try this:

#include "udf.h" DEFINE_DIFFUSIVITY(protondiff,c,t,i) {

real D=0.0; int zone_ID = THREAD_ID(t);

if (i == 1){

if (zone_ID==2)

{D = 2.03e-15;}

if (zone_ID==3)

{D =2.03e-15;} return D;}

else if (i == 2){

if (zone_ID==2)

{D = 8.91e-10;}

if (zone_ID==3)

{D = 9.90e-10;} return D;}

else if (i == 3){

if (zone_ID==2)

{D = 1.9285e-11;}

if (zone_ID==3)

{D = 2.03e-11;} return D;}

else if (i == 4){

if (zone_ID==2)

{D = 4.275e-11;}

if (zone_ID==3)

{D = 4.5e-11;} return D;}

else if (i == 5){

if (zone_ID==2)

{D =2e-15;}

else if (zone_ID==3)

{D = 2e-15;} return D;}

else { return D; }}

That worked great, thanks! The numbers for species were from 0-4 though. Cheers, Ryan