The purpose of this model is to demonstrate how GoldSim can calculate hydraulic functions dynamically. This particular model uses a dam outlet example to calculate discharge from an outlet structure as conditions change through time. The majority of the model logic is contained in a single Script element (See element called "Discharge"), which calculates the headloss and resulting discharge through each outlet and subsequently the total discharge from the dam.
The outlet structure consists of 3 outlet pipes and a 4th pipe for draining the reservoir at the very bottom (Drain Pipe). Water flows into these pipes into the outlet tower, which is a large vertical cylinder. At the bottom of the tower, a long discharge pipe leads to a cone valve, which drops the pressure before discharging to the river. A tailwater level is assumed at the outlet, which drives the hydraulic gradeline moving back upstream.
Depending on the headlosses and flows in the discharge pipe, the water level in the outlet tower may or may not affect the flow through 1 or more of the outlet pipes. GoldSim starts with an assumed flow rate and calculates the resulting headlosses. A solver function is used to iterate to solve for a solution in which the flows and headlosses all agree. This solver repeats on each time step and the discharged water is removed from the total volume in the reservoir, causing the water level in the reservoir to drop on the next time step.
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