Rotating-frame relative effective potential
= Rotating-frame relative effective potential
{title2=$\psi_{\mathrm{eff}}=\psi+\tfrac12\Omega_b^2R^2$}
For a bar rotating with constant pattern speed $\Omega_b$, use $\psi_{\mathrm{eff}}=\psi+\Omega_b^2R^2/2$ in the force convention $+\nabla\psi$. The centrifugal acceleration is its added gradient. This is the negative of the usual physical effective potential $\Phi_{\mathrm{eff}}$; Coriolis acceleration is separate.