The unsteady base flow around an axisymmetric bluff body at a Reynolds number of 320,000 is simulated using a high-order implicit large eddy simulation (ILES) approach. Accurate prediction of bluff-body base flow is challenging due to massive flow separation and unsteady turbulent structures in the near-wake region, which are not adequately captured by conventional Reynolds-averaged Navier–Stokes (RANS) methods. High-fidelity numerical schemes with low numerical dissipation are therefore required to resolve such flows. In this study, ILES of the separated base flow is performed using the high-order flux-reconstruction solver PyFR [1]. The results are validated against wind-tunnel experiments [2] through comparisons of the base pressure coefficient and near-wake velocity fields. Simulations including a support strut are also conducted to assess aerodynamic interference effects associated with wind-tunnel mounting. In the presentation, we will explore in detail the effects of the support strut on the base pressure distribution and the resulting unsteady wake flow structures.