Modifying actuationDiskSource to inject turbulence kinetic energy
 

I am new to C programming so it is a little confusing as to what is going on with the actuationDiskSource. I am ultimately looking to modify the source to make it non-uniform, possibly unsteady, and to modify other quantities such as k. Can anyone explain what is going on in the source code here, and how, for example, I could add a source for k?