In many situations, such as flows passing through a section of the channel widths, the sudden opening of the flow duct either on the horizon plane or on the vertical plane, there is a possibility of reverse flow. Couette Flow, which is flowing in channels with moving walls that move in opposite directions, can simulate these types of flows. For the first time, it is attempted to obtain and draw velocity contours and depth-averaged velocities in a rectangular channel with moving walls. The walls move at equal velocities and opposite directions to each other. This is done for channels with varying width-to-depth ratios. It is predicted that velocity contours and depth-averaged velocities will be very similar to the Couette flow between the two plates when the channel depth is greater than the width. The proposed model is used for this purpose by Maghrebi (Adv Water Resour 29:1504–1514, 2006. https:// doi. org/ 10. 1016/j. advwa tres. 2005. 11. 007). To simulate reverse flow, it is sufficient to consider the shear stresses direction on the walls to be in opposite directions to each other. The linear stress distribution is the best assumption to consider the shear stress distribution for the channel bed situated between the two walls. In this case, a hypothetical boundary is formed perpendicular to the middle of the cross section of the channel bed. It flows on both sides of the boundary having equal velocities but different signs. One of the interesting points in this phenomenon is drawing dimensionless isovel contour. The zero average velocity at the channel cross-section results from zero average discharge. Large amounts of dimensionless isovel contour occur in the vicinity of the moving walls that is difficult to imagine how the isovel contours were formed.

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