Question on the governing PDE

[Raocp]

Hi Lars, great job! Here I have one question about the governing equations (of T, Psi) you referred to. It looks that the equation for T is

What about the equation for Psi? Any reference or link would be appreciated. Thank you.

[maxiimilian]

You probably found the equations by now but for future reference I would like to point to Saltzman (1962): https://doi.org/10.1175/1520-0469(1962)019%3C0329:FAFCAA%3E2.0.CO;2. The governing equations are derived in chapter 2.