Low Reynolds number fully developed two-dimensional turbulent channel flow with system rotation

Theoretical and experimental studies have been performed on fully developed two-dimensional turbulent channel flows in the low Reynolds number range that are subjected to system rotation. The turbulence is affected by the Coriolis force and the low Reynolds number simultaneously. Using dimensional analysis, the relevant parameters of this flow are found to be Reynolds number Re* = u(*) D/nu (u(*) is the friction velocity, D the channel half-width) and Omega nu/u(*)(2) (Omega is the angular velocity of the channel) for the inner region, and Re* and Omega D/u(*) for the core region. Employing these parameters, changes of skin friction coefficients and velocity profiles compared to nonrotating flow can be reasonably well understood. A Coriolis region where the Coriolis force effect predominates is shown to exist in addition to conventional regions such as viscous and buffer regions. A flow regime diagram that indicates ranges of these regions as a function of Re* and \Omega\nu/u(*)(2) is given from which the overall flow structure in a rotating channel can be obtained. Experiments have been made in the range of 56 less than or equal to Re* less than or equal to 310 and -0.0057 less than or equal to Omega nu/u(*)(2) less than or equal to 0.0030 (these values correspond to Re = 2 U-m D/nu from 1700 to 10 000 and rotation number Ro = 2 \Omega\D/U-m up to 0.055; U-m is bulk mean velocity). The characteristic features of velocity profiles and the variation of skin friction coefficients are discussed in relation to the theoretical considerations.