The thermo-hydraulic analysis of laminar mixed convection (forced and natural) through a horizontal channel-enclosure assembly equipped with a heated hollow hemispherical source (constant power of 20 W) in the bottom of the enclosure and different inlet air velocities equivalent to Reynolds number ranged (2.8814, 14.407, 28.814, and 43.221) are obtained numerically with the help of COMSOL Program. The impact of altering the input air velocity on the thermo-hydraulic properties is explored here as part of the research project. Good agreement was found between the derived numerical findings and those already established in the literature. The pressure profile throughout the channel is not altered via the numerically simulated increase on the positive y-axis. Increasing the incoming air velocity increases the natural convection induced via the heated source, which in turn increases the blending of cold and hot air within the enclosure and reduces the temperature gradient across the channel. As a result of the circumstances preventing slippage, the channel area exhibits the characteristic velocity profile of laminar flow, which consists of zero velocity at the channel walls and the maximum velocity in the channel's middle. The area of the recirculating streamlines is expanded by the rise in the velocity of intake air. As the incoming air velocity increases, so does the average Nusselt number.