Direct numerical simulation of turbulent flow and heat transfer in a square duct rotating along its spanwise direction

Turbulent flow and heat transfer in a square duct rotating along its spanwise direction is investigated by direct numerical simulation. The spatial terms in the governing equations are discretized by second-order central difference scheme and the time terms are discretized by the Adams-Bashforth scheme. The influence of rotation on the streamwise velocity, crosswise velocity and the mean temperature is analyzed. The results show that the mean velocity and the mean turbulent kinetic energy decreases with the increase of rotation number when the centrifugal buoyancy force is neglected. The mean turbulent kinetic energy of Ro_τ=1.5 decreases by 15 percent compared with that of Ro_τ=0. If the effect of the centrifugal buoyancy force is taken into account, for the radially outwards flow, the mean velocity and turbulent kinetic energy increase with rotation number compared with those without the effect of centrifugal force, and the results are converse for the flow radially inwards. It is found that the mean turbulent kinetic energy increases by 17 percent for the radially outwards flow at Ro_τ=1.5 compared with that of Gr_τ,L=0, but it decreases by 43 percent for the flow radially inwards.