The fully developed turbulent flow in an annular pipe with radius ratio of 1/2 is investigated for Reynolds numbers based on hydraulic diameter and bulk velocity ranging from 12000 to 46000. The study is carried out processing data obtained from wall resolved large eddy simulations employing the dynamic subgrid scale eddy viscosity model of Germano et al. (1991) as modified by Lilly (1992). Scaling in wall variables shows that the turbulence intensities in the inner radius region are systematically less than the corresponding plane channel data, while the differences in the outer radius region reduce considerably. Because of the transverse curvature the total shear stress deviates from the linear distribution by as much as 12% in the inner wall region at y+ = 100. The curvature effects decrease as the Reynolds number is increased. Thus in the low Reynolds number range similarity arguments have to be considered with augmented caution with respect to the plane channel case

Effects of the Transverse Curvature on the Statistics of Fully Developed Turbulent Flow in an Annular Pipe

VACCA, Andrea
2002

Abstract

The fully developed turbulent flow in an annular pipe with radius ratio of 1/2 is investigated for Reynolds numbers based on hydraulic diameter and bulk velocity ranging from 12000 to 46000. The study is carried out processing data obtained from wall resolved large eddy simulations employing the dynamic subgrid scale eddy viscosity model of Germano et al. (1991) as modified by Lilly (1992). Scaling in wall variables shows that the turbulence intensities in the inner radius region are systematically less than the corresponding plane channel data, while the differences in the outer radius region reduce considerably. Because of the transverse curvature the total shear stress deviates from the linear distribution by as much as 12% in the inner wall region at y+ = 100. The curvature effects decrease as the Reynolds number is increased. Thus in the low Reynolds number range similarity arguments have to be considered with augmented caution with respect to the plane channel case
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11591/199150
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