User Defined Scalar (UDS) vs Species transport
 

What is the difference between UDS and species transport in Fluent?. I know UDS is for a passive scalar and species transport can simulate the chemical reaction during flow. So what is the difference between UDS and scalar transport without chemical reaction?

As I have come to understand: User Defined Scalars(UDS) are used for passive scalar transport and Species Transport are used for Active scalar transport
Ref
1) https://www.cfd-online.com/Forums/fl...ve-scalar.html
2) https://www.cfd-online.com/Forums/si...ve-scalar.html