Abstract:The aeration capacity of the spillway tunnel with high speed flows was analyzed by model experiment from the macroscopic aspect.The results showed that the aeration capacity of the complement wind tunnel in the mid-gate chamber would not increase as the rate of flow increasing.The aeration capacity is related to the Froude number of the flow out of the gate.The aeration capacity which arises from the self-aerated flow increases as the Froude number increasing.When the water level of reservoir is constant

the air output of the tunnel increases to a critical value then decreases sharply along with the increase of the Froude number.When the radical gate is fully opened

the air output of the tunnel decreases as the Froude number increasing.The air concentration of the outflow increases with the increase of the Froude number.