Cosmological simulation of a galaxy cluster undergoing a major merger at z = 0.14. Four left-most panels, clockwise from top left: Projected shock-dissipated energy rate, gas pressure, gas density, and dissipation-weighted Mach number, respectively. Projections have a depth of ±7.5 Mpc from the cluster centre. Right-most panels: enlarged cut-outs showing slices through the midplane of the projection. The white, dashed box indicates the size of the upstream region in our idealised shock tube simulations. The merger drives a shock wave out to the cluster outskirts. The collision of this shock wave with an accretion shock leads to the production of a thin shell of compressed gas (see white arrow). A movie of this process can be found here.