Hello,
I am curious if the Hammer Wave Speed Calculator is unique to Hammer or if it originated from a published document. Thanks. -Garrett
Garrett,
HAMMER's wave speed calculator tool uses an equation developed by Korteweg to calculate wave celerity based on the bulk modulus of elasticity, Young's modulus, liquid density, wall thickness, diameter and a pipeline support factor (based on the support type such as anchored throughout).
The equation can be found in the help documentation, under Contents > Bentley HAMMER Theory and Practice > Water System Characteristics > Celerity and Pipe elasticity.
Regards,
Jesse DringoliTechnical Support Manager, OpenFlowsBentley Communities Site AdministratorBentley Systems, Inc.
Dear Jesse,
According to Korteweg's equation, in a network where we have pipes of different diameters and of different materials (GRP, DI etc) the wave speed should vary from segment to segment. If we use the wave speed calculator in the model, it asks for one young modulus and one pipe wall thickness only. It changes wave speed in all the pipes together. Of course, it gives a warning of number of pipes its going to change. I normally calculate it seperately and give it as an input. Many consultants, to play safe, suggest to use the wave speed calculator icon.
What is your suggestion on that?
Hi - you should only use the wave speed calculator on pipes that share the same properties as each other.
If you have a number of different pipe types in your model, you can select all of the pipes of the same type, then in the 'Features' section of the calculator pick 'Selection' to only update the wavespeed on the selected pipes.
Also remember that this equation is just an approximation. It is a good idea to check the systems sensitivity to a range of different wavespeeds.
Mal Sharkey
Bentley
Hi,
I am only having troubles with the wavespeed calculator...
In my situation I have a Steel pipeline that has a HDPE liner tightly inserted on the inside to decrease friction losses.
Is there a way in Hammer insert the thicknesses and properties of both materials to calculate the combined wavespeed?? Or if the HDPE liner is inserted tightly can I assume that the pipeline will have the overall elastic properties of steel??
Any suggestions??
Thanks,
Violette Edwards
Hello Violette,
The below forum thread may help you:
http://communities.bentley.com/products/hydraulics___hydrology/f/5925/t/26659.aspx