Structures and Intermittency in Rotating Pipes

Abstract

The study of turbulence through a pipe which rotates about its axis is of fundamental interest, partly because of the practical applications but also because the rotation introduces a variety of new flow structures. Since the intermittency phenomenon is likely to be related to these structures, the effect of rotation on velocity structure functions of different orders may allow some insight into the relationship between moments and structures. Orlandi & Fatica [1], using a direct numerical simulation at low Reynolds number and at relatively high rotation rate, showed that the structures everywhere across the pipe differ significantly from those in the stationary pipe. Clearly, the major interest is on the changes to the near-wall structures because of their interrelationship to the wall friction, turbulent energy production and energy dissipation rate. In a subsequent study [2], the simulations were extended to higher rotation rates with the aim of providing budgets for each of the Reynolds stresses which would in turn be used for improving/streamlining RANS turbulence models of rotating flows. The budgets were found to change at all locations across the pipe although the major changes occurred near the wall.