Total density ρ (top) and temperature T (middle) along the loop at t ≈ 2750 s in the extended isobaric simulation, shown in physical units. The velocity v is overlaid as white arrows in panel (a), illustrating the converging siphon-like flows directed towards the apex condensation. Panel (c) shows the loop-integrated total entropy S(t) = ∫(p/ρ^γ) ds, normalised to its initial value, as a function of time. The entropy decreases monotonically throughout the linear evolution, consistent with the non-adiabatic nature of the dominant thermal continuum mode.