Effect of the side walls on the unsteady flow in A duct of rectangular cross-section

In this paper, the effects of the side walls on the unsteady flow in a duct of rectangular cross-section are considered. In order to show the effects of the side walls on the flow, two illustrative examples are given. One of them is the unsteady flow due to an applied pressure gradient in a duct of rectangular cross-section. The other is the unsteady flow in a duct of rectangular cross-section moving parallel to its length. These effects depend on the values of the aspect ratio. The variations of the velocity and the volume flux with respect to the aspect ratio show that these are appreciable effects of the walls on the flow. It is found that the required time to reach the steady-state for the flow with side walls is shorter than that for the flow without side walls.