Filling analysis of 2013

[Anonymous]

Dear Moldflow support staff,

When I calculated the same filling analysis with 2012sp2 and 2013 and compared them, I found that two are explicitly different.

That's why I guessed the solver for filling is changed in 2013.

But my sales representative told me that the solver for filling is NOT changed and we confirmed it with Autodesk.

Now I get confused and would like to know the correct answer about this issue.

1. whether the solver for filling is changed or not?

2. If not what is the reason why different results are obtained?

Thanks in advance,

Noritaka Inoue

[Anonymous]

Just a guess from looking at the plots is that the bottom plot has inertia effect turned on, and the top picture does not.  Double check your settings.

Tim

[Anonymous]

Tim, thank you for your reply!

> the bottom plot has inertia effect turned on

 Inertia effect turned off in my setting and the log file showed me that indeed the Stokes solver (not　Navier-Stokes) is used.

But I agree with you that the bottom seems to include the inertia effect.

I have another example, I can't give you it right now though, which is the calculation counting both gravity and inertia.

In that case, the results were different between 2012sp2 and 2013 too.

[KAZU_ITO · Accepted solution]

Hello Inoue-san,

Autodesk support engineer has been working with your reseller engineer for this issue. Our engineer has given the following answer to your reseller engineer last Friday. It seems there was small response time lag, so we informed this post to our reseller engineer and we will provide same information on the forum.

We are improving solver for each release, so you may see some difference when comparing with previous version results. We usually provide information of key improvements by release note and validation report.

In this case, “Accuracy Improvements Implemented in the 3D Flow Solver” of 2013 validation report described this improvement.

You can download this PDF from Subscription center. Please login to subscription center (Japan site: http://www.autodesk.co.jp/subs_signin / English site: http://www.autodesk.com/subscriptionlogin), then select [Download] from “Product Enhancements” (Japanese menu: 「拡張機能」の[ダウンロードリンク]), [Autodesk Simulation Moldflow 2013 Solver Changes and Validation Documents], [asmi2013_3d_flow_accuracy_improvements_en.pdf].

This documentation describe following information on page 3.

Flow front improvements

The main enhancements in the algorithms used for flow front advancement are as follows:

Previously, the velocity of flow front nodes was not solved directly, except when the Simulate inertia effect option was turned on. Velocities were extrapolated from the filled nodes onto the flow front. This was done for speed and stability, but it is slightly less accurate. Now, the flow front node velocities are solved whether the inertia option is on or off. This means that when inertia is off (which is the default condition), the prediction of the flow front shape and fill pattern will be more accurate compared to previous releases.

I hope this help.

Best regards,

Kazuhiko Ito

[Anonymous]

Dear Ito-san,

Thank you so much!

Your answer is just what I want to know and now my question is completely solved:)

Best regards, 

Noritaka Inoue