The results from the numerical investigations of both steady and unsteady circular turbulent jets impinging orthogonally on a flat surface are presented. The inlet velocity waveforms analysed consist of steady jets, square jets, triangular jets, and sinusoidal jets. In the case of unsteady jets, both intermittent and pulse jets are examined. Reynolds number (Re) ranges from 5100 to 23000, the normalized distance from the nozzle to the target surface (Z/D) spans from 2 to 12, and the frequency(f) varies from 0 to 200. The 3D simulation is carried out using finite volume based software Ansys Fluent. To ascertain the validity of the numerical approach, a rigorous validation process was undertaken, focusing on the Nusselt number, a critical parameter for characterizing heat transfer performance. Baseline studies were conducted on steady jets. Unsteady jets outperform steady jets at low Reynolds numbers. However, as the Reynolds number increases, the heat transfer capabilities of unsteady jets decline in comparison to steady jets, even though there is a marked increase in turbulence intensity for the unsteady jets. There exists a threshold frequency beyond which an unsteady jet demonstrates superior performance compared to its steady equivalent. Among the unsteady jets studied, the intermittent square jet provides the highest effectiveness, whereas the sinusoidal jet exhibits the poorest performance across all operating conditions. The secondary peaks observed in steady jets at low Z/D and high Re are absent in unsteady jets. The boundary layer thickness is maximum for steady jet and minimum for intermittent square jet. The thickness of the boundary layer rises as Z/D increases and diminishes with an increase in f. At higher Z/D, the jet expands more prior to striking the surface, resulting in a thicker boundary layer near the surface.