Relative deviation from the initial profile for the 1D simulations described in Sect. 4.1 at t ∼ 1100 h. Shown are results for the temperature T, the BVF N, and the temperature gradient ∇ = ∂ log T/∂ log P, respectively. Solid lines correspond to cylindrical geometry whereas dashed lines denote the results for spherical geometry. Only the surface of the computational domain is shown to emphasize the change at the outer radial boundary. The deviations are even smaller in the inner part which is not shown here.