Flow Pattern and Wall Shear Stress through Unsymmetrical Branch in Steady Flow

The wall shear stress and the flow pattern in a 45 degree unsymmetrical branch model in steady flow have been studied experimentally. The model, made of Plexiglas, consists of the parent tube (D₀ = 24 mm) and the daughter tube (D₁ = 14 mm). The curvature of the outer wall in the daughter tube and of the flow divider was R_D = 3.5D₀ and R_c = D₀/8, respectively. The wall shear stress was measured using an electrochemical method at the Reynolds number of 500, 800 and 1200, and the flow pattern was visualized by dye injection. Approximately 150 electrodes were embedded in the median plane of a branch tube. The ratio of the flow rate in the daughter tube to the total flow rate in the upstream parent tube is about 0.25, which corresponds to the ratio of the cross-sectional area downstream. The flow through this branch was characterized at the outer wall of the daughter tube, at the outer wall of the parent tube and near the flow divider. In particular, at the outer wall of the daughter tube, flow separation did not occur although the helical flow appeared.