In recent days, the behaviour of wind flow around the buildings receives more interest among urban planners, architects, researchers and wind engineers. Hence, these wind flow patterns are assessed extensively using CFD (Computational Fluid Dynamics) simulations, as it re-creates the atmospheric and wind tunnel environment following the turbulence parameters. This paper presents a logical assessment using IDDES (Improved Delayed Detached Eddy Simulation) turbulence model in CFD for predicting wind pressure coefficients and flow features on and around a 300:1 scaled setback tall building model at 0° and 90° AOI (Angle of Incidence) under open terrain condition. The computation is based on gird sensitivity study and validation with Boundary Layer Wind Tunnel (BLWT) experiment measurements. The evaluation shows that the downdraught and downwind effects are suppressed by the increasing wind pressure distribution along the height. The results demonstrate that IDDES can reproduce wind pressure coefficients and aerodynamic coefficients of the setback building accurately. The maximum deviation of the wind pressure coefficients (Cp rms) is found to be 12% in CFD when compared with wind tunnel measurements. Besides, the CFD simulation demonstrates the wind flow distribution patterns, size of re-circulation, wake separation zones and velocity profiles in a three-dimensional plane which are quantified concerning the width of the building. © 2019, Tsinghua University Press and Springer-Verlag GmbH Germany, part of Springer Nature.