Learning Forum

[bbcn]

I'm trying to use design of experiments (DoE) to optimize dimensions of a nozzle based on maximizing the inlet mass flow with constant inlet pressure. Multiphase is based on air and liquid water where water enters from the inlet and the air is the medium. I have achived this type of enviorenment by patching and setting the volumetric fraction of the water as 0 in the interior, such that water enters to the air medium and the volumetric fraction change in the water in the medium can be observed. The analysis runs flawlessly however when I create design points (DP's) and and update the solution for each in DoE, updates fail. I recieve the error association A5, floating point exception. Here is the list of things I have done so far:

• Set a couple failed design points as current and checked geometry and mesh, no problems here.
• Set the analysis from transient to steady, no changes.
• Initialized the analysis standard and hybrid as well, it still fails to update the DP's. Though, I can solve it manually.
• Run the analysis manually for a couple failed DP's, it runs and prints the results. But when I don't patch, floating point exception fail occurs.

My strong guess is DoE does not patch automatically. For analysis to make sense and run without an error, patch is needed. Therefore, my questions are:

1. Is there a way that DoE patches while updating DP's?
2. If not, is it possible to do this analysis without patching, so that it remains multiphase?

Regards,

Babacan

[Murari Iyengar]

Hi,

You can use Execute Commands to include a patch TUI at the start of your calulcations. Kindly refer to 35.17. Executing Commands During the Calculation (ansys.com) on Executing commands. To patch, you can use /solve/patch followed by the necessary inputs. You can find it in Fluent GUI in the console section. 

[bbcn]

 

Hi Murari,

Thanks for the reply. I have created an execute command in GUI to patch at flow time = 0 s using the command texts below:

/solve/patch/phase water volume-fraction 0.0 fluid-surface_body

Also tried,

/patch/patch/phase water volume-fraction 0.0 fluid-surface_body

However, it still fails to patch. I’m new to this concept so I’m not 100% sure if my syntax is correct. Let me know if you require more information.

Regards,

Babacan

 

[Murari Iyengar]

 

You don’t type the word “phase”. You type water directly. 

 

One way to find out the command is to type it in the console. You can hit Enter and you’ll get the list of available options. You can type one of the options and hit again and Fluent will show you a sub-list of options.

 

You can then put them together. In the above example, the TUI command will be /solve/patch water fluid () mp 0.1

Similarly, you can find out for your case and put this command in Execute Commands. 

 

 

[bbcn]

 

Hi again,

I was able to patch the zone starting from Iteration number 1 by using the command text below:

/solve/patch water fluid (fluid-surface_body) mp 0

The command executes once the analysis is run and removes the need to patch manually through initilization window.

Thank you for your help.

Regards,

Babacan