A note on the azimuthal momentum transport in infinitely arrayed rod bundles

The azimuthal momentum transport plays an important role in the flow field through non-circular domain. In order to obtain the information on the azimuthal momentum transport in infinitely arrayed rod bundles theoretically, an integral analysis is performed on the axial momentum equation. By integrating the axial momentum equation from the wall to the maximum velocity line, a simple and useful relation between the integral azimuthal momentum transport and the wall shear stress distribution is derived in terms of the azimuthal angle and the pitch-to-diameter. The contribution of azimuthal Reynolds stress and secondary flow to the azimuthal momentum transport is analyzed for well-known experimental data. It is expected that the derived relation may be useful to understand the turbulent structure in rod bundles and to confirm the experimental results for azimuthal Reynolds stress and secondary flows as well