Unsteady RANS simulation of turbulent flow and heat transfer in ribbed coolant passages of different aspect ratios

The flow and heat transfer in ribbed coolant passages of aspect ratios (AR) 1:1, 4:1, and 1:4 are numerically studied through the solution of the unsteady Reynolds averaged Navier–Stokes (URANS) equations. The URANS procedure, which utilizes a two equation k–ε model for the turbulent stresses, is shown to resolve large-scale bulk unsteadiness. The computations are carried out for a fixed Reynolds number of 25,000 and density ratio of 0.13, while the Rotation number is varied between 0.12 and 0.50.