Decision time and real time. Fluent.

- October 10, 2023 at 2:02 am
  
  javat33489
  Subscriber
  
  Hi all. If I use the non-stationary solution method, can the total solution time be taken as real time in life? Or should we think about quasi? And after the decision, make a graph, for example, pressure / time.
  My task is two chambers, there is a hole between them, in one of the chambers there is high pressure. Through the hole, liquid under pressure will fill the second chamber; I need to calculate how long it will take to fill the second chamber and select the hole.
- October 10, 2023 at 2:26 pm
  
  Rob
  Forum Moderator
  
  Does the amount of liquid in the first or second chamber alter the flow rate?
  - October 10, 2023 at 5:41 pm
    
    javat33489
    Subscriber
    
    Initially, in the first chamber the pressure is 10 MPa, in the second it is atmospheric. I need to calculate how long it will take for the water to flow into the empty chamber, and then I will adjust the cross-section of the hole to get the time I need. Therefore, I need to see the time on the chart as close as possible to life.
- October 11, 2023 at 8:33 am
  Rob
  Forum Moderator
  OK, and is the second chamber vented? You have two options:
  - Model the whole lot using transient, which could take days (or more) depending on scale.
  - Model steady state assuming the second chamber doesn't influence the flowrate and there is enough pressure & material in the first that it's a uniform flow.
  I can't tell you that, you need to think about it and work out how to defend any assumptions later on.