VELOCITY-MEASUREMENTS OF THE LAMINAR-FLOW THROUGH A ROTATING STRAIGHTPIPE

Some measurements have been obtained for the axial velocity of the ful ly developed laminar flow in a circular straight pipe with radius a, w hich is rotating with constant angular speed OMEGA about an axis perpe ndicular to its own axis. A diode laser LDA system was mounted togethe r with a circulating pipe flow system on a rotating table for the expe riment. According to previous analyses and calculations, there exist f our types of axial velocity distributions that result from the various effects of the secondary flow on the main stream via the convection a nd Coriolis effect for different values of R( = w(m)'a/nu) and R(OMEGA )(=OMEGAa2/nu), where w(m)' is the mean axial velocity and nu is the k inematic viscosity of the fluid. The present study provides experiment al validation for the previous theoretical and numerical analyses. Exp eriments have also been carried out for studying the asymptotic nature of the slow flow in a rapidly rotating pipe (R(OMEGA) much greater th an 1 and R(OMEGA) much greater than R) and the rapid flow in a slowly rotating pipe (RR(OMEGA) much greater than 1 and R much greater than R (OMEGA)).