A series of transient numerical simulations investigating the pressure drop and thermal performance in a rectangular channel with symmetrical ramps has been carried out. These simulations help in understanding the relationship between obstruction geometry and heat transfer characteristics. Initially, a simulation is conducted for a rectangular duct without obstructions based on these boundary conditions. Subsequently, sections with obstructions featuring ramp angles of \(20^{\circ }\) , \(30^{\circ }\) , and \(45^{\circ }\) are simulated under the same conditions. The oscillatory flow frequency is set at 5 Hz for all configurations, with the maximum velocity and flow time calculated accordingly. The hot inlet, representing the hot end of the Stirling engine, is set at 773.15 K, while the cold inlet, representing the cold end, is initially set at 288.15 K. Analysis shows an increase in the average Nusselt number and friction factor with increasing ramp angle. The thermal performance parameter and pressure drop both decrease with increasing ramp angle.