<p>This study presents a numerical investigation of the combined effects of frequency and dimensionless amplitude of sinusoidal pulsating flow on the thermal performance of the SEGS LS-2 parabolic solar collector. The analysis combines a MCRT method for non-uniform solar flux distribution with sinusoidal inlet conditions implemented through user-defined functions (UDFs) in ANSYS Fluent using the RNG k-ε turbulence model. The effect of pulsating flow parameters (frequency: 0.2–6 Hz; dimensionless amplitude: 0.3–0.9) on the heat transfer characteristics, including Nusselt number and thermal efficiency, was evaluated using Syltherm 800 oil as the heat transfer fluid (HTF) at a Reynolds number of 4761. The results showed that at a frequency of 5 Hz (Strouhal = 0.131) and a dimensionless amplitude of 0.5, the time-averaged Nusselt number reaches 5.1 and the time-averaged thermal efficiency reaches 77%, while according to previous findings, the highest thermal efficiency in steady state is reported to be 74%. Increasing frequency turbulence in the viscous sublayer causes the growth of the hydrodynamic layer and improves heat transfer. Higher frequencies (e.g. 6 Hz) cause turbulence to freeze and limit the increase in performance. These findings highlight the potential of frequency-controlled solar collectors in areas with high solar flux. The use of frequency valves, while saving additional costs, also increases the thermal efficiency by 3-4.5%.</p>