Accepted: 20 April 2018 Analysis of the vortical structures arising in the system with respect to their control parameters is an important fundamental study. Studies in this regard have mostly been paid attention on a free convective cavity flow. Relatively few studies have been devoted on the characteristics of the vortical structures arising in the mixed convection cavity flows. Thus, it is aimed to analyse the vortical structures arising in a free and forced convective flow of air in a cubical cavity using the direct numerical simulations. Governing equations of this problem, expressed in dimensionless form are solved by using the finite volume method. The simulated results are corroborated with benchmark solutions. Numerical solutions are obtained for wide range of Reynolds number (Re) and Richardson number (Ri)(the mixed convection parameter). The flow and thermal characteristics are analysed using isotherms, velocity magnitude, vortex corelines and average Nusselt number. The simulated results show that the large values of Ri decrease the total heat transfer rate thus the conductive heat transfer prevails. While when Ri takes the small values and for amplified values of Re the complex 3D features are clearly seen and the vigorous forced convection enhances the global heat in the system.