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Simulation CFD

3 Posts
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Registered: ‎11-08-2012

Water hammer

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11-28-2012 07:54 AM



I try to simulate water hammer in pipeline with two valves. The simulation works fine if both of the valves close at the 0 time step, but i have e.g 20ms time difference between the closes(now we don't care about the closing velocity, it's infinitly fast). So somehow i have to define this delay between them.

I've tried to do this with use the time curves when i define the transient boudary condition. The defined value doesen't follow the function what i gave.

My system looks like this:



Valve 1 closes at 0 s.

Valve 2 closes 20ms later, the predifed velocity-time curve:


The velocity change at valve 1:


The velocity change at valve 2:


As you can see, the closure happens at the same time, no matter what i defined earlier.

Please give me ideas how can i implement/simulate this 20 ms delay!


Thanks a lot!


3 Posts
0 Kudos
Registered: ‎11-08-2012

Re: Water hammer

11-28-2012 01:29 PM in reply to: sirkoattila

Finaly solved.

after SS run->giving the valve1 closing TR boundari condition->transient run from 0s to 20ms->giving the valve2 closing TR boundari condition->continue transient run as long as you want