Large eddy simulation of turbulent flows in a rotating concentric annular channel

Abstract

Turbulent flow through a concentric annular channel rotating around its axis is investigated numerically by use of large eddy simulation (LES) coupled with a localized one-equation dynamic subgrid-scale (SGS) model (LDM). The objective of this study is to investigate the behavior of turbulent flow near the inner and outer walls of the rotating concentric annular channel and to examine the effectiveness of the LES technique for predicting the turbulent flow subjected to system rotation. The Reynolds number, based on the global friction velocity u τ and the annular channel gap width d, is 640, and the rotation number N = 0–20, which is defined as N = 2 Ωd/ u τ with Ω being the angular velocity of the rotating annular channel. To validate the present computation, LES on turbulent flows in a rotating pipe and in a concentric annular channel are carried out, which shows that the LES results are in good agreement with available experimental data and direct numerical simulation (DNS) results. Then, turbulent statistics in the rotating annular channel, including the resolved velocity, turbulence intensities, Reynolds stresses, turbulence skewness and flatness, and flow structures near the walls, are investigated. The budgets of turbulent kinetic energy and Reynolds stresses are calculated to examine the turbulence production rate, velocity and pressure-gradient correlation, turbulence diffusion, dissipation rate and Coriolis force term near the outer and inner walls.