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Hi
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some questions have been remained unanswered. I copied them below. Please have a look and let me know your ideas:
Jesse

3- It is obvious that waves' can interact on each other. You can strike on water (e.g. in a pool) and you strike again in a distance of first strike. Two waves (which are produced from two strikes) have interaction on each other and a new wave will be constructed. It is a simple sample which shows waves' interactions.
Meanwhile it seems that vaporing and condensation together (cavitation) use energy and do not rely on friction or frictionless. Are you assured about your thought?

And two below questions remains to be thought more by you:

 #2- Transient is result of changing in momentum and momentum is result of changing in velocity. Velocity is a vector parameter. It means that Velocity's change is due to changing in velocity's quantity or velocity's direction. All discussions about transient Analysis (in your AWDM or Help documents) speaks about Transient as result of changing in AMOUNT of velocity not changing in DIRECTION of it.
Assume a pipe with no operations or branches, valves or ... but there is a Tee along the pipe. Changing in velocity's direction makes momentum and therefore it makes a transient. Am I right or I make mistake and Transient is due to JUST velocity's quantity?

 #3- According to 'Wave Reflection and Transmission' on P. 589 and Figure 13.6 (b) on P. 592 of your book, when wave reaches to a dead end point, then r=1. Hf is defined as dH0+dHr. What does it mean? What is it good for? Does it mean an increased wave (2*H0) will be formed while the wave returns? If a pressure gauge be installed near the end of the pipe, it have to show Hr (which is equal to H0) or Hf (=H0+Hr). What do you think?

Mike
 
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  • 1) My previous answer was regarding the effect of cavitation and column collapse in a frictionless system in Bentley HAMMER. I can confirm that it does not introduce energy loss.

    2) This again is a theoretical question beyond the scope of Bentley products, but I will try to answer. Although a pipe may change directions such as a 90 degree bend, we know that this certainly does not cause a transient in itself. HAMMER can analyze transient forces at end points so the force from such a change in pipe direction can be quantified.

    3) HAMMER's Sample1 model is a good example of wave reflection. "Res" is a reservoir and "Val" is a valve that closes and stays closed (acts as a dead end).


    Regards,

    Jesse Dringoli
    Technical Support Manager, OpenFlows
    Bentley Communities Site Administrator
    Bentley Systems, Inc.

Reply
  • 1) My previous answer was regarding the effect of cavitation and column collapse in a frictionless system in Bentley HAMMER. I can confirm that it does not introduce energy loss.

    2) This again is a theoretical question beyond the scope of Bentley products, but I will try to answer. Although a pipe may change directions such as a 90 degree bend, we know that this certainly does not cause a transient in itself. HAMMER can analyze transient forces at end points so the force from such a change in pipe direction can be quantified.

    3) HAMMER's Sample1 model is a good example of wave reflection. "Res" is a reservoir and "Val" is a valve that closes and stays closed (acts as a dead end).


    Regards,

    Jesse Dringoli
    Technical Support Manager, OpenFlows
    Bentley Communities Site Administrator
    Bentley Systems, Inc.

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