Combined maps of logarithm of pressure (left panel, upper half), density (left panel, lower half), axial velocity (right panel, upper half), and jet mass fraction (right panel, lower half) at t ≃ 9 × 10⁴   s for S1. The plots make use of the axisymmetric nature of the simulation. Jet mass fraction equals 1 for pure jet material, 0 for pure obstacle material, and values in between indicate mixing. Units are cgs.