Hello all, I hope I can get the support I need here... I am attempting to solve a kind of tedious pair of coupled diffential equations, and after a lot of trial and error I still can't get them to solve. After getting the boundary conditions defined and non-dimensionalizing the equations, I get an error which states: "The return value of this function must match the problem size." I haven't run into this error before, so I'm at a loss as to what might be wrong with the setup (perhaps the equations aren't converging?) Any help or guidance you can give me would be greatly apprecaited. I have attached a screenshot of the problem setup for thos who are interested...