Characteristics of turbulent flow in the annuli with smooth and rough surfaces

The structure of turbulence of fully developed flow through three concentric annuli with rough walls shown in Fig. 1 was investigated experimentally for Reynolds number range of Re =15000−66000. Time mean velocity distribution, friction factor, turbulence intensity and turbulent kinetic energy in annuli of three radius ratios of α=0.26, 0.39 and 0.56 for four cases of roughness type were measured. The results show that the structure of turbulence in these asymmetric flows is significantly different depending on the roughness wall position. An experimental study for the case of a smooth annulus was also carried out for a benchmarking purpose. The velocity distributions and friction factors are also presented and discussed.