Hi,
During hammer simulation two issues occured:
1- the pressure , the first 400 sec in simulation HGL fluctuate near the upper value - max pressure (No.1), after that HGL moves to position No.2 for little time then it moves to position No.3 till the end of the simulation (1200 sec).
2- when I reduce time interval of simulation from 0.05 sec to 0.01 sec the vapor volume disappears.
Kindly I need illustration for possible causes for these events.
Abdallah, you had posted in the Communities Feedback forum which is intended for questions about the site itself. I have moved your post to the OpenFlows Forum where you can get help from OpenFlows specialists.
Abdallah Magdy said:1- the pressure , the first 400 sec in simulation HGL fluctuate near the upper value - max pressure (No.1), after that HGL moves to position No.2 for little time then it moves to position No.3 till the end of the simulation (1200 sec).
It's hard to say what specifically is causing the "fluctuations" without seeing the model. What type of transient event are you modeling? It could be due to interaction with vapor and/or air pockets, it could be related to stability issues with a certain element configuration (such as a valve, hydropneumatic tank or pump specific speed), an issue with the selected transient friction method, or something else. If you have not done so already, be sure to animate the profile path to get a better understanding of how things are interacting during the transient simulation. If this does not help, provide a copy of the model and steps to reproduce: Sharing Hydraulic Model Files on the OpenFlows Forum
Abdallah Magdy said:2- when I reduce time interval of simulation from 0.05 sec to 0.01 sec the vapor volume disappears.
This may suggest that the 0.05 seconds is not small enough to accurately capture fast changes occurring during the transient simulation, or possibly an indication of some other instability with the model (which could be "real" due to the complexity of wave interactions, or unrealistic due to some other model instability). Again without a deeper understanding of the transient event and model configuration it is impossible to tell for sure. We may need to see a copy of the model.
Regards,
Jesse DringoliTechnical Support Manager, OpenFlowsBentley Communities Site AdministratorBentley Systems, Inc.
Transient
Hello Abdallah,
Thank you for sending the model. I computed the active scenario (Valve Closure - 2) and did not see any vapor forming when computing for either 0.05 seconds or 0.01 seconds. If you are looking at a different scenario, please let us know.
Otherwise, you are using an older version of HAMMER. It is possible that upgrading may see some improvement. The latest version of HAMMER is 10.04.00.108.
Scott
Hi Abdallah, all I see in your reply is "Transient". Did you mean to say something else? If you still need help after reviewing my previous answer, please explain in more detail and we'll be glad to help.
Hello Scott,
I re-uploaded the model after proper orientation of the scenario i want to understand the behaviour of hgl due to pump shut down failure.