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Hammer Hydraulic Model

Dear All,

I have performed hammer analysis with different scenarios of valve closure. I have used TCV and valve characteristic curve. I would really appreciate If you review my model and give your comments especially regarding discharge coefficient in my model is correctly applied or there are errors in this simulation.

Thanks and Regards,

Syed Ahmed.

Parents Reply
  • Thanks Sushma,

    Yes, I saw user notification in the model. Following are the notifications I got from my model. I have also uploaded my model. I would really appreciate If you see that model.

     1.The wavespeed or length approximations deviate excessively from the entered values. Reduce the time step, or lengthen short pipes and/or subdivide longer pipes." Transient Engine

     2.The period between path histories has been increased by a factor of 22 to limit the number of path records to 1002498." Transient Engine.

    Thanks & Regards,

    SA

Children
  • Hello Syed,

    I do not see any specific issues with the valve characteristic curve or the discharge coefficient used. You would want to check the manufacturer data to make sure they are correct. If there is no TCV currently there, a review of some different valves may give you some guidance on the settings to use. 

    As for the user notifications, HAMMER adjusts the pipe lengths or pipe wave speed values during the transient simulation so that a pressure wave can travel from one end of the pipe to the other in even increments with the time step. If the relative change is large, the first user notification can be generated. This most often occurs in short pipes. More information on this can be found here: Understanding length/wave speed adjustments and their impact on results.

    For the period between path histories notification, this occurs because there is currently a limit on the size of the transient output file. To account for this, the results you see in transient profiles and time history results can sometimes be multiplied by a certain factor. Adjusting the number of report points or other options in the transient calculation options can reduce this multiplier. More information on this can be found here: The period between path histories has been increased by a factor of X to limit the number of path records to Y

    Regards,

    Scott

  • Thanks Scott for describing all aspects of in detail.  I will also simulate with different types of valve. 

    Thanks,

    SA