inlets/outlets Not created automatically/Not enough memory to run radiation

[RobHarker]

Autodesk CFD Forum;

I have a rather complicated largescale model 1 of 24 section with one curvilinear and 3 flats.  Put a 100Pa pressure BC on the "inlet" and a 0 velocity reverse normal on the "outlet".  Using variable air material on atmosphere model and set glass as the material on the greenhouse section.  Using IV2016 -)> CFD 2016 to analyze.  Shouldn't it have created an inside volume and automatically set the inlets and outlets for the velocity fields IAW the BC's ?

I've tried the window material to no avail on the larger curvilinear surface. 

Dell Precision T7500 8 core xeons 96GB RAM  ... When running the radiation experiment I run out of memory according to CFD at 99% iteration point yet my monitor shows only ~18GB used.

I need to see these flow patterns and not once of dozens of tries has CFD reported back inlets/outlets in the messages and I don't think it is creating the special internal volume.  Do I need to run the IV shell command on the greenhouse section?

Any help in this matter will benifit us greatly.

Thanks in advance,

R. Harker

Messages

==============================================

Mesher process started...

Loading model...

Loading mesh sizes and constraints...

Meshing...

Surface meshing... generating surface mesh

Surface meshing... smoothing surface mesh

Volume meshing... creating volume mesh

Volume meshing... optimizing volume mesh

Volume meshing... smoothing volume mesh

Mesh contains 664830 nodes and 3466762 elements.

Performing mesh quality check...

Saving mesh...

Meshing completed.

Updating model database...

Model database updated.

Updating mesh database...

Mesh database updated.

Building solver model file...

Solver file written.

Initializing ...

Control file processing complete

Check Out motion License: Successful

Authorization verified

Processing input ...

Mesh input complete

Processing results input ...

Results input complete

Processing BC input ...

Computing restart BC data ...

Calculating BC data structures ...

Calculate wall distance for 664269 fluid nodes

Wall distance calculation done in (3 + 😎 seconds. Max distance = 3.09835e+06

BC data structures complete and saved

Analysis Initialization Complete

Input processing complete

** FINITE ELEMENT SUMMARY FOLLOWS...

664830 Total Nodes, 664269 Fluid Nodes , 561 Solid Nodes

3466762 Total Elements, 3462177 Fluid Elements , 4585 Solid Elements

0 Inlets 0 Outlets 0 Unknowns

*********** ANALYSIS STARTED ***********

Turbulent Compressible Flow is ON

Turbulence model: Standard k-epsilon

Intelligent Wall Formulation: ON

Flat lines detected in Convergence Monitor - Auto Stop.

Begin Post-Processing Calculations ...

Post-Processing Calculations Done

Begin Post-Processing File Output ...

Post-Processing File Output Done

Analysis completed successfully

[RobHarker]

Dear CFD community;

Well I deleted the inlet & outlet face in Inventor 2016 --- transfered to CFD 2016 1st directly and got a closed volume where the geometry tool in CFD would not allow me to remove the faces CREATED by CFD on import.  So maybe it is creating the enclosed volume and having an issue with the original part because I'm supposed to see 2 volumes.  So I tried to export indirectly as a SAT file and ended up with the same thing.

As you can see in the screencast the "select by face"(& volume) in the void fill geometry tools is grayed out and not accessable.  So using the edge tool will not allow me to select a face on my model.  Is there a setting in CFD that toggles the face selection in void fill to be active?

CFD seems to have issues in the import modules.  I've included the Inventor ipt so Autodesk will be aware of the issue. ... when's the 2017 version coming for the academic community?

Thanks,

RobHarker

[Jon.Wilde]

I think the problem here is that this is a surface. CFD really needs a solid to do what you are asking. Could you try this and see if it works a little better?

Thanks,

Jon

[RobHarker]

@Jon.Wilde & the CFD community;

I think I'm getting somewhere on this.  I'm using a thin-shell solid and it appears to be working with the initial and boundary and initial conditions set forth.

I simulated the sunshine shining on the ground with a 75W/m^2 Heat flux (Florida).  Since it is transient the velocity magnitiude flows  ar high at first then taper off.  Do you think I'm on the right track?  Other than convection which doesn't seem to be working the flows for this scenario anyway seem to be working.  I used the geometry function to create the internal mesh and external "atmosphere".

Also what I mean about a bug in the importer from IV2016 is that when I do do a fully solid section it doesn't seem to come in as a shell with surfaces missing.  Also no matter what I do within the solver "message window" dialog, it has NEVER assigned inlets and outlets yet this is why I need to set conditions on my known inlet and outlet. 

The CFZ file not compatible or too big for your servers.

Thanks fpor all your help,

Robert

[RobHarker]

Here is the CFZ file zipped.

[RobHarker]

Here is a zipped AVI animation.

[Jon.Wilde · Accepted solution]

Hi Rob,

Sorry it took a little bit to get back to you, I missed this thread.

I can certainly suggest a few more things, sorry if they seem a little blunt 🙂

1. Disable Auto Forced Convection, this is running flow first and thermal second - not what you want here I suspect
2. You have gravity acting in the -z direction but the sky in the global y direction - should they not be opposite directions rather than normal to each other?
3. Enlarge the domain and set some BC's on it - I think I might use a P=0 and temp on the top surface, or maybe just a temperature could work here too
4. You still cannot assign internal BC's - the internal velocity, pressure and radiation conditions need to be removed - unless you suppress the greenhouse from the mesh (not what you need think?). 
5. All of these interal BC's are applied to glass, which I cannot understand? Should the ends of the greenhouse be open to the air?
6. There is a gap between the wall of the air and the greenhouse, is this realistic? You might need to draw the air in CAD also

And the important question - are you basically just trying to model an open greenhouse in the sun?

Thanks,

Jon

[RobHarker]

I abandoned the curved surfaces and made a faceted model and it seems to be working;