Unsteady RANS and Large Eddy simulation of the flow and heat transfer in a wall bounded pin matrix

Four calculations, two using LES with respectively 18 and 76 million computational cells and two utilizing a URANS approach on a 2 million mesh with sophisticated first and second moment closure approaches; the f-model and the EB-RSM combined to the EB-GGDH, have carried out for the flow through a wall bounded pin matrix in a staggered arrangement with a heated bottom wall at a Reynolds number based on the gap velocity and the diameter of the pins equal to 10, 000. Comparisons of the pressure drop, the pressure coefficient distribution, the mean and rms values of the steam-wise velocity component and the Nusselt number distribution along the bottom wall showed clearly that using a first moment closure is not adequate for the present case. Although the wall-resolved LES with 76 million cells shows a superior behavior, the second moment closure exhibits very interesting results.