Modeling multiple tapes

[Agri-Valley]

I have been modeling a dual hose dripline system with a single hose based on the posts in the How To... forum. I realized that my hose loss for the modeled single line is higher than my calculated losses; almost a 1 psi difference. I have attempted to rectify the modeled single line hose loss by changing the roughness coefficient but it has not changed the headloss.

[jovivier]

Unfortunately there is not enough information for an informed response to your question.
Are you modelling two tapes as one tape or modelling two tapes as one sprayline?
If you are modelling tapes as one tape the roughness factor is not used in the analysis of the headloss, the Kd of the tape is used. I will need to search for the formula to calculate what the new Kd should be so please let me know if this is the case.

The How To post is based on mirroring tapes as spraylines for functions such as designing the flushing main which cannot be undertaken on tapes.
If the spraylines have had the roughness factor changed it is possible that the change has not come through in to the internal database. The best way to fix this is to close the design, change the roughness factor to something else and save and close the database. Open the design so the internal database updates. Then save and close the design and change the roughness factor back to the number you had previously. Save and close the database. Does the analysis now reflect the new roughness factor?

Did you know you can create groups of tapes in a block such as 2 (or more) tapes per group?

[Agri-Valley]

What I am refering to as tapes is for example a 20mm PE hose with 1 gph inline dripper @ 36". We typically put two hoses per row coming off a single riser from the manifold. I have been modeling a single hose as a dual hose by doubling the flow and increasing the diameter. The work around I found for this is by adjusting the diameter of the dual hose until the headloss matches the headloss for the single hose.

I am aware of the grouping hoses but I was under the impression it would have 2 riser assemblies if grouping 2 hoses.

[jovivier]

Since Pro V10.5 a change was made to allow for fractions of items to be placed into assemblies. This is useful when one riser is used to feed more than one lateral. To produce a correct bill of materials via Computer Selection of Fittings read the tips for assemblies with or without the riser included.

http://www.irricad.com/irricad/download ... YSTEMS.doc

[mblack]

Since Pro V10.5 a change was made to allow for fractions of items to be placed into assemblies. This is useful when one riser is used to feed more than one lateral. To produce a correct bill of materials via Computer Selection of Fittings read the tips for assemblies with or without the riser included.

http://www.irricad.com/irricad/download ... YSTEMS.doc

When one riser is used to feed more than one lateral, and one wishes to produce a correct bill of materials and an accurate hydraulic model, which method will produce the most accurate design?
For example, using the grouping method allows for an accurate hydraulic representation, but the bill of materials would need to be adjusted. Alternatively, when grouping is off, the bill of materials is correct (besides tape quantity), but the tape characteristics would need to be manipulated in order to accurately represent one tape as two tapes in terms of hydraulics.

Thank you for the help!

[jovivier]

Using groups and then the method outlined in the document is one way to do it.
Note that Version 16 includes the ability to add negative amounts of fittings into assemblies that may be needed to offset what IRRICAD automatically selects. This means that you don't need to remember to remove certain fittings after the fact.

The IRRICAD Team