A symmetric Mach 12·76 hypersonic flow in a 90° corner, formed by 30° swept back intersecting 8° wedges, was investigated in detail through numerical simulation using locally conical Navier-Stokes equations. Three different numerical schemes for spatial discretisation, MacCormack central differencing, van Leer’s flux vector splitting and Osher’s flux difference splitting, were studied to compare their capabilities to capture both strong shock waves and thin shear layers. Comparison with experimental data was made to validate the simulation. The numerical simulation provided further insight into the flowfield and a pair of counter-rotating vortices were discovered near the junction of the corner.