Abstract
When the flow of underground diversion channel shifts from the open channel flow to the pipe flow, the air is enclosed in the tunnel. In this study, the effect of the air enclosed in the tunnel on the flow of underground diversion channel was analyzed using the slot model. It was shown that it was necessary to consider the compressibility of the air and the discharge of the air from vertical shaft in order to analyse the effect of the air, and water level of the vertical shaft and pressure in the tunnel increased when the air is enclosed in the tunnel.
