Openflow Water GEMS 2023: Velocity of flow is Zero but it should be 140 m/s

I am trying to create a situation where water is being discharged from a pipe connected to a Reservoir. When I calculate the flow velocity through pipe it is coming 140 m/s, however, In waterGEMs flow velocity is coming Zero. Please guide what should I do?

As We can see through calculation that velocity should be 140 m/s however, Velocity as appearing in WaterGEMS is zero. Can Someone please guide how can I correct the velocity in WaterGEMS.