To calculate the wave speed in manually

Some ask for calculating wave speed in manually for water hammer analysis is it possible.Because of the manual calculated values are more less than software calculated values.What is your opinion for this situation.

Best Regards

W.K,Dharmadasa

Senior Engineer 

Parents
  • Hello,

    Your post was moved to the OpenFlows Forum. I assume you are using HAMMER. 

    Are you saying that your calculated values for pipe wave speed are different from the values calculated in HAMMER using the Wave Speed Calculator Tool? What equation are you using? HAMMER uses the equation mentioned in the following article from our Wiki: Equation used in Wave Speed Calculator tool

    HAMMER's calculated wave speeds are an estimate based on the data input such as pipe wall thickness, bulk modulus, etc. The equation used is a standard one and should produce fairly accurate wave speeds, but if you have a different way of calculating them, you are free to manually enter the wave speed in the pipe properties or flextable (or globally in the calculation options).

    One suggestion would be to try a sensitivity analysis - compute the transient simulation with HAMMER's calculated wave speeds, then set up another scenario (with child Transient alternative, as the wave speeds are stored there) with your own calculated wave speeds. Compare the transient results such as the envelope in the Transient Results Viewer, to see if the results you're interested in are sensitive.


    Regards,

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

    Answer Verified By: Dharmadasa Wickramasekara 

Reply
  • Hello,

    Your post was moved to the OpenFlows Forum. I assume you are using HAMMER. 

    Are you saying that your calculated values for pipe wave speed are different from the values calculated in HAMMER using the Wave Speed Calculator Tool? What equation are you using? HAMMER uses the equation mentioned in the following article from our Wiki: Equation used in Wave Speed Calculator tool

    HAMMER's calculated wave speeds are an estimate based on the data input such as pipe wall thickness, bulk modulus, etc. The equation used is a standard one and should produce fairly accurate wave speeds, but if you have a different way of calculating them, you are free to manually enter the wave speed in the pipe properties or flextable (or globally in the calculation options).

    One suggestion would be to try a sensitivity analysis - compute the transient simulation with HAMMER's calculated wave speeds, then set up another scenario (with child Transient alternative, as the wave speeds are stored there) with your own calculated wave speeds. Compare the transient results such as the envelope in the Transient Results Viewer, to see if the results you're interested in are sensitive.


    Regards,

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

    Answer Verified By: Dharmadasa Wickramasekara 

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