Numerical simulation of turbulent pipe flow
Résumé
Many experimental and numerical studies have been devoted to turbulent pipe flows due to the number of applications in which theses flows govern heat or mass transfer processes: heat exchangers, agricultural spraying machines, gasoline engines, and gas turbines for examples. The simplest case of non-rotating pipe has been extensively studied experimentally and numerically. Most of pipe flow numerical simulations have studied stability and transition. Some Direct Numerical Simulations (DNS) have been performed, with a 3-D spectral code, or using mixed finite difference and spectral methods. There is few DNS of the turbulent rotating pipe flow in the literature. Investigations devoted to Large Eddy Simulations (LES) of turbulence pipe flow are very limited. With DNS and LES, one can derive more turbulence statistics and determine a well-resolved flow field which is a prerequisite for correct predictions of heat transfer. However, the turbulent pipe flows have not been so deeply studied through DNS and LES as the plane-channel flows, due to the peculiar numerical difficulties associated with the cylindrical coordinate system used for the numerical simulation of the pipe flows. This chapter presents Direct Numerical Simulations and Large Eddy Simulations of fully developed turbulent pipe flow in non-rotating and rotating cases. The governing equations are discretized on a staggered mesh in cylindrical coordinates. The numerical integration is performed by a finite difference scheme, second-order accurate in space and time. The time advancement employs a fractional step method. The aim of this study is to investigate the effects of the Reynolds number and of the rotation number on the turbulent flow characteristics. The mean velocity profiles and many turbulence statistics are compared to numerical and experimental data available in the literature, and reasonably good agreement is obtained. In particular, the results show that the axial velocity profile gradually approaches a laminar shape when increasing the rotation rate, due to the stability effect caused by the centrifugal force. Consequently, the friction factor decreases. The rotation of the wall has large effects on the root mean square (rms), these effects being more pronounced for the streamwise rms velocity. The influence of rotation is to reduce the Reynolds stress component and to increase the two other stresses and . The effect of the Reynolds number on the rms of the axial velocity (