FLOWS IN A CURVED RECTANGULAR CHANNEL (2ND REPORT, VELOCITY MEASUREMENTS IN THE DEVELOPING REGION OF LAMINAR FLOW BY USING LDV.

An experimental investigation is carried out. The fully developed steady laminar flow in the entrance region of a curved rectangular channel is studied under the velocity profile of Poiseuille flow at the inlet and the Dean number is 220. The channel has an aspect ratio of 2 and a curvature ratio of 8. The axial velocity and the radial component of the secondary velocity are measured by using a laser doppler velocimeter (LDV) at 15 sections from the inlet ( theta equals 0 degree ) to the outlet ( theta equals 270 degree ) of the channel. The developing secondary flow is clearly presented and is in good agreement with the results obtained from a flow visualization carried out by the authors.