Hi,
I am using HAMMER Update 3 - Build 10.03.01.08. I have a modeled a simple circular surge tank and turbine. I am checking the water level within the tank (thru the analysis detailed report) and the values that I am getting are too high and even have negative elevations. Are these really the values from the analysis, or, there might be something wrong with the model? Thank you.
Hello Jenelyn,
You need to be sure about your input data, you can check the turbine model from sample folder, C:\Program Files (x86)\Bentley\HAMMER\Samples. Compare your input data and modeling conditions, which shall help you.
Also check for any user notifications that might give idea, if there any issues with the model.
Here is surge tank technote that can help you.
Modeling Reference - Surge Tanks
If this doesn't help you then please elaborate your issue.
Regards,
Sushma Choure
Bentley Technical Suppport
Can I send you the model so you can check? Also, there is always a notification on wave speed suggesting to split long pipes.
What exactly is the user notification you are getting? There is one related wave speed or length adjustments, which more typically occurs in short pipes rather than long ones.
If you need to send the model, you can use the steps found here.
Scott
Hi, please see uploaded file. thanks.
The notification that I am getting says, "The wavespeed or length approximations deviate excessively from the entered values. Reduce the time step, or lengthen short pipes and /or subdivide longer pipes".
You want to have your pipes as long as reasonably possible. You can also adjust the time step to be smaller. Or, you could possibly ignore the warning if the results make sense and look correct to you - it is up to your engineering judgment.
The best ways to avoid this user notification is to either merge the short pipe with another (or remove the short pipe altogether, if it is a dead end node) or to manipulate the time step. A combination of these may be needed in some cases.
Please read below wiki, for detailed information on this.
Understanding length/wave speed adjustments and their impact on results