Turbulent Flow in a Rotating Two Pass Ribbed Rectangular Channel

Abstract

Laser-Doppler anemometry has been applied to approximately two-dimensional turbulent air flow in rotating two pass channel with turbulator of rectangular cross section (AR=3:1). The axis of rotation is normal to the axis of the duct, and the flow is radially outward/inward. The duct is of finite length and the walls are isothermal. Two sided oppositely ribbed channel including one sided ribbed U bend of p/e=8 at e/DH=0.27 are experimentally conducted with ReD=5000 and 10,000. The main features of the flow, reattachment length, recirculation zone, and mean velocity as well as turbulent intensity and shear stress distributions are presented in ribbed ducts. The measured flow field is found to be quite complex, consisting of secondary cross-stream flows due to the Coriolis effects and centrifugal forces with rib-roughened surfaces.