Running EPS in WaterGems using tanks

Question

HI, I am trying to run a distribution model in EPS in which the source is a over head tank on the hillock which serves a colony in which every building consists of a service overhead tank. But when I run this model flow is getting multiplied and not showing the actual hydraulics. Can you help me in this TWS all Tank.wtg I attached the model also for your reference. 
 Thanks in advance, 
 Eswar

Stephen Jackson · Answer

Try experimenting with the Calculation Options. I tried the following settings: 
 Hydraulic Timestep: 0.05 
 Convergence Check Frequency: 5 
 Convergence Check Cutoff: 500 
 Damping Limit: 0.01 
 Trials: 10,000 
 Accuracy: 0.0001 
 
 With these settings, the model ran successfully with no errors and only a few warnings. The results are that almost all of the tanks fill up completely and then stay essentially full to the end. The PRVs are just opening and closing to let demand through, and almost none of the zones have any tanks that are providing actually buffering to establish a consistent hydraulic grade. 
 The flow through the pipes is very erratic, but within reasonable bounds, as all the PRVs are constantly trying to open and close to provide exactly the right headloss to meet the demand. 
 In other words, with the full tanks and the numerous PRVs and lack of hydraulic grade buffering, this is a very tricky model to get accurate results for, so it requires very small timesteps and high number of trials.

Sushma Choure · Answer

Hello Eswar 
 You have uploaded only .wtg file, please upload .wtg.sqlite file as well without which the model cannot be opened. 
 How are you modeling building service overhead tanks, you could put a junction for this with total demand of the building.

Running EPS in WaterGems using tanks

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