Wall shear stress and periodical oscillation induced in side branch at right angle branch in laminar steady flow

In the present study, the wall shear stress and the flow structure in the right angle branch have been experimentally studied in laminar steady flow. The side branch bifurcates at right angle from the trunk, and both upstream and downstream corners at the entrance of the side branch are square edge. In the trunk, the wall shear stress takes very large value at the upstream corner and the change of wall shear stress around the upstream corner is comparable to that around the flow divider. It is noticed that there is a periodical oscillation of velocity downstream of the separation region in the side branch. The Strouhal number is independent on the Reynolds number in the side branch. There would be a probability that this phenomenon is similar to that of Karman vortex, i.e., the flow in the side branch periodically oscillates.