Mass-weighted disk eccentricity, Eq. (4), of the circumprimary disk versus time. The 2D model predicts an eccentric disk, achieving quasi-equilibrium at ⟨e_d⟩ ≈ 0.3 (green circles). The solid line is an average performed every 10 T. In comparison, the 3D model predicts a much less eccentric circumprimary disk (orange circles), ⟨e_d⟩ ≈ 0.03. The red curve represents an average over 10 T intervals.