Hello,

I would like to find the Retention time distribution of a tracer in pond. Using the additional variable option, how do I add a pulse mass (or a point mass) of say 1kg only at time=1s?

Thanks!

- Create the Additional Variable - Include the Additional Variable on the Domain > Fluid Models panel using the 'Transport Equation' option - Use a CEL expression to define the amount of the Additional Variable entering the domain through an inlet. A suitable expression might be:

step((t - 1[s])/1[s])*1[kg s^-1]*step((2[s] - t)/1[s])

this will give a flow rate of 1 [kg/s] for 1 second between t=1[s] and t=2[s]. You can plot the expression in CFX-Pre to check it looks OK. Regards, Mike