negative concentration

Andrew Garrard

Hola all,

I am running a UDS to simulate the concentration of a species. (very similar to the built in fluent species model). I am setting the uds flux (rate of reaction) to be a function of the value of the UDS (or a value of the concetration) . I am getting a situation where there is a negative value of the UDS, which is not only unphsical, but also I don't understand how the value could be derived when the flux is proportial to the value. Do you know why this is happening and how to fix it?

Thanks.