ESDU CFD-BPG 11010 provides the Best Practice Guidelines recommended by ESDU for the CFD modelling of pressure loss@ discharge coefficient and flow characteristics in square- and knife-edged orifice plates. These Guidelines are based on the extensive ESDU CFD validation studies discussed in ESDU TN 10013 and may be used in the modelling of engineering applications such as flow-meters@ cooling holes@ valves@ fuel lines@ hydraulic systems@ air conditioning systems and water pipe systems. This CFD Guide may be used with any finite volume Reynolds-Averaged Navier-Stokes (RANS) CFD code with low-Reynolds-number turbulence modelling and correlation-based 'bypass' transition modelling capabilities.