Granular flows have some applications in industry and nature which can be described and modeled similarly. Debris flow, snow avalanches and landslide are examples of natural events along with silos, hoppers and fluidized beds as industrial cases where flows of grains usually encounter with solid objects. In this paper, cylindrical objects of different radii with controllable surface roughness are exposed to a stream of inelastic hard disks in the absence or presence of gravity. A granular shock wave is developed around the solid object whose features are dependent of different geometric and physical parameters. In simulations, the event-driven algorithm has been used with binary inelastic collisions. The surface of cylindrical object is either smooth or covered by hard disks as the same ones in the main stream. Stresses due to successive collisions are calculated in normal and tangential directions at the surface of cylindrical object. Voronoi tessellation is performed to visualize the packing density in particle level. Results revealed that the coefficient of restitution has considerable effect on the features of granular shock wave where gravity displayed mild influence. However, the presence of gravitational acceleration raises the stress with a quadratic function though the ratio of stress and the flow pattern reaches to steady state fairly quickly. The surface roughness in the same order as the flow particles size yields a double amount for stresses in comparison to a perfectly smooth surface. The smaller object size was also found to tolerate larger force fluctuations with a weaker quality of flow branching. For local stresses, the peak value of fluctuations can reach 5 times greater than its mean. (C) 2011 Elsevier B.V. All rights reserved.