Static and dynamic characteristics of turbulent flow in a closed compound channel

The hot-wire anemometry technique was employed to study the velocity distribution and dynamic characteristics of the flow in two types of closed compound channels. The compound channels were built using two rectangular tubes attached to the walls of a wind channel separated by a distance d. In this configuration, a narrow gap is connected to a main subchannel. The results revealed an interesting flow that was quite similar to a mixing layer. All axial velocity profiles presented turning points at the main subchannel/narrow gap interface. By using quantities from the mean flow velocity distribution, the flow could be described by a hyperbolic tangent function, and a Strouhal number was suggested as well. Regardless of the channel type, the dimensionless frequency was almost constant, resulting in a Strouhal number of approximately 0.10.