CCM+ Natural convection

AJ

CCM+ HELP! I'm trying to simulate natural convection from a heated fin into air. The air density and temperature around the fin vary as expected, but there seems to be no air movement. The model is setup with a solid continuum and a fluid continuum. The model for the fluid is as follows: Steady, Laminar, Segegrated Fluid energy, Segegrated flow, Gravity, Ideal Gas, 3D, Static, Gas.

I'm probably missing something simple, but any help would be great. Thanks.