Thermofluid dynamics of an unconfined steady two-dimensional laminar jet impinging on an isothermal protruded heater is numerically studied for low jet inlet Reynolds number between 50 and 250. Results are shown for a range of impingement distances between 1 and 10 for Prandtl numbers 0.71 and 7.56. The volumetric entrainment increases with increasing h/w and decreasing . The reattachment distance of the wall jet appears to increase with and shows discernible deviation from the backward-facing step flow prediction for . Correlations are presented for average heater surface and sidewall Nusselt numbers as functions of Re and h/w for and . In an overall convection dominant heat transfer, a relatively warmer and diffusion-dominated recirculation zone is identified adjacent to the sidewall with a low Nusselt number, which enhances significantly at when is increased above 100. At a low impingement distance, integrated kinetic energy flux shows greater magnitude in the impingement region but with a higher rate of decay. The integrated heat flux is greatly influenced by , and the effect is more pronounced at . Self-similar behavior is observed for the velocity and heat flux profiles throughout the length in the developed region and for the temperature distribution over the heater surface. Both high and high h/w seem to adversely affect the self-similar behavior owing to a slower wall jet development.