Direct numerical simulation (DNS) of a fully developed turbulent flume how with passive heat transfer is performed using the finite-difference method with 50 400 grid points;The bottom wall is heated at a constant rate. The Reynolds number, based on the flume depth and the bulk velocity, is 2855, and the Prandtl number is 0.72. The results are satisfactory, and the comparison between the present results and those of other DNS investigations shows distinctive differences in the near-wall region owing to the difference in the thermal boundary conditions.