Literature suggests that waveform shapes has significant effect on the thermal behaviour of the pulsating jets. However, only a single numerical investigation is reported so far, that analyses the influence of waveform shapes on the thermal behaviour of circular orifice SJ. Present numerical analysis reports the effect of waveform shapes on the flow and thermal characteristics of circular SJ. The three different waveforms considered are sinusoidal, triangular, and rectangular waveform. The actuation frequency and jet to surface axial distance are varied in the range of 50-150Hz and 1-15, respectively. The Reynolds number is kept constant at 2100 for the entire simulation. The average Nusselt number for triangular waveform is found to be 18.52% and 28% higher compared to the sinusoidal and rectangular waveform. The flow study reveals that triangular waveform has higher jet spreading compared to rectangular and sinusoidal waveform. In addition, the mass flow rate for triangular wave (z/d > 6) at the resonance frequency (f = 150 Hz) is found to be 46.1% and 18.75% higher than the rectangular and sinusoidal waveforms, respectively. The results obtained from the present numerical investigation provide significant guidance for the efficient design of SJs for thermal management of compact electronic devices.