A conventional car silencer is incorporated with several plates containing perforations for the deduction of sound waves from a car exhaust gases. Perforations in tubes or plates facilitate in developing a large variety of comprehensive models for sound attenuation. Exhaust gases passing through unimpeded straight perforated pipe forces the sound waves to dissipate the energy, thereby optimizing the performance and minimizing the back pressure exerted on the engine. On the other hand, the poorly designed perforation can deteriorate the engine performance by increasing the flow back pressure. Owing to the fact, in this work, the numerical model is based on the installation of the perforated plate with distinguishable hole sizes in a uniform circular pipe oriented normally to the mean gas flow direction. The essential function of the perforated plate is to route the gas flow in a non-uniform distribution of holes with various diameters and consequently, establishing the fully developed flow regime inside the pipe. The comprehensive description of flow performance according to the various perforated plate shapes are presented and compared to situations with no perforated plate. This work aims in demonstrating the importance of perforated plate by numerically investigating three different models, namely flat, convex and concave framed plates accomplished with pressure drop. Further, the study shows various flow characteristics associated with the velocity and turbulent intensity profiles as well as the flow uniformity depending on the perforated plates adopted. These results offer a practical guide to the best design of pipe with perforated plates.