To analyze the influence of the tapered form of the two upper vertices of a rectangular cube placed in a channel and the impact of the insertion of hollow in the center of the obstacle, a three-dimensional study was executed using K-ω SST turbulence model. Different models of the form of the cube were presented to examine the features of the flow with a Reynolds number Re=4×104. The turbulence kinetic energy, 2D and 3D time-averaged streamlines, trace-lines, streamwise velocity profiles, pressure profiles were obtained using the ANSYS CFX calculation code and the finite volume method were employed for resolving the governing equations. The streamlines showed in the model of the tapered cube with hollow a formation of another vortex downstream of the cube at the outlet of the hollow. For the streamwise velocity, there are two recirculation zones: one logarithmic zone due to the main flow, the other is a lower parabolic return zone due to the recirculation vortex.