The majority of our CFD simulations are axisymmetric. The advantages of being able to analyze in 2D versus 3D are tremendous for us. Many of our parts are long tubes (40" to 100" long) with wall thicknesses from .031" to .062" and diameters from 1" to 4". Some tubes have a .0004" silver or copper plate on the OD or ID along its entire length. The plating has a significant impact on heat flow but the plating is impractical to model. This is because the plating is so thin compared to the tube wall thickness (77 to 155 times thinner) and because the plating is so long compared to its thickness (100,000 to 250,000 times longer), meshing causes the plating and the tube to have a godzillion elements.
The ability to select an edge and define it as a "surface part" and then to specify its thickness (example: .0004" thick) like we can do in 3D would be a great asset.
We have multitudes of 2D axisymmetric analyses that take about 2 minutes to run but the view factor calculations (radiation on) takes about 20 minutes. In other words it takes 10 times longer to calculate the view factors than it does to run the analysis. Many times we'll create several scenarios by cloning the previous scenario. We keep the geometry the same but we'll modify material like changing aluminum to stainless steel, or changing a thermal conductivity from 20 to 60. None of these changes should trigger a re-calculation of the view factors but it does. This is unnecessary and wastes a lot of time. Can this be changed? I don't know if it happens in 3D but it does happen in 2D.
The 3D Viewer is currently a 32bit application. This really limits its use to smaller models.
This should be upgraded to 64bit to be inline with us only supporting 64bit platforms.
After solving for Transient analysis, i need to see the effect on flow (flow vs time plot). But currently such plot is not available as a direct output unlike velocity, press, temp. Same is the case for plots available at monitoring points. So for this I need to extract flow values for every iterations / time steps from either summery file or from bulk results by creating a plane. This is very tideous procedure!
NEED "FLOW VS TIME" AS A DIRECT OUTPUT.
Calculating the mass weighted total pressure is important for internal compressible problems, valves turbines and compressors. It is the desired variable for compressor companies to run sub models to optimize the inlet and outlet transition regions before and after the compression stages. Last week I meet with a compressor company that is happy using another CFD tool for the compressor stage design but only have 1 user. For the inlet and outlet transitions they are don’t more design work and feel that our CFD is a better fit and cost effective to roll out to 100 design engineers to right size new products to address new market needs. To fit into their workflow they need to know the Total Pressure at the outlet and map effectively to their current compressor CFD tool.
I've heard a couple requests for a formal certification program, so requesting futher comments here.
Are you interested in being certified? What would your expectations be? Are there other programs you have been through that are good models?
I would like to be able to adjust the number of iterations during solving so I can cause the simulation to terminate earlier or later than originally intended, but not necessarily right now.
So if I originally asked it to run 1000 iterations, but based on how I see the solution evolving now I want it to stop at 500, I would like to be able to enter that during solving.
This could be useful during automatic mesh adapatation cycles where the convergence is happening sooner or later than expected. I may want the current cycle to terminate soon so it can go to the next mesh level.
Alternatively if I underestimated the number of iterations then I would like to be able to extend the run time without starting and stopping the simulatin - this is especially important for large files/remote solves.
Being able to adjust other termination parameters while solving would also be useful (i.e. stop time in a transient, as opposed to iteration number; adjust the intelligent solution parameters to looser or tighter criteria; etc.)
I am working with BIG models ( BIG Buildings )
Starting the model in Revit and launcing the CFD directly.
I happend many times that I am not able to close the internal volums and afer many many hours I found few gaps of about 1 mm ,
In the construction arena with 100 m long building and wall width of 20 cm I do not care about 1 mm gape.
I am looking for a flag that I will be able to indicate the minimal gap to close the internal volume to be 1 cm.
I need to complete a thermal simulation on the nose of an aircraft constructed of a carbon-fiber resin material. I have values for the in-plane and out-of-plane thermal conductivity. Considering the geometry of the cone, I can't enter the thermal conductivities oriented with a rectilinear coordinate system (as is necessary in the material editor for this type of material). The analysis is for cooling an electronics system through the aircraft skin.
With the ongoing prolifieration of composite materials, having this capability would be significantly beneficial. If Autodesk could incorporate this ability into their simulation tool, it would be a product differentiiating capability.
Create a phase change combustion module to show proper heat release and flame impingements. Having the ability to see post combustion chemical breakdown such as NOx or CO would be great but to be able to predict temperatures around combustion equipment is the primary desire.
I created groups during simulation setup, and I now what to access these in results. Currently this is only possible with wall results.
- in an architectural application I want to show my structure group as a solid color while displaying vector and plane results through the space
- in an electronics application I want to make my chip group all into summary parts
It is not clear which fields on the edit dialogs are editable, as the table appears entirely flat aside from a couple ellipses that hint at dialogs:
However, when you click in an interactive cell its input control is then exposed. For example:
I am proposing these controls are shown by default so it is clear which fields can be edited, and in what fashion.
Often while checking the final meshcount I have to count the number of digits to make sure if the mesh is of the order of hundred thousands, millions or over 10 million. How about showing the number of elements by separating three digits with a comma? I know it's rather a trivial requiest but can come handy to quickly get the sense of enormity of mesh. There had been times where I have seen my colleagues submitting a job of 23 million mesh, thinking it was a 2.3 million mesh!
Please increase the number and variety of color maps available in the legend, and/or allow the user to import or create their own color map. Even the limited legends in Sim Mechanical are more flexible and useful.
The present color maps are very limited, and out of date with regards to current standards of data visualization - and may even cause users to be in violation of accessibility standards. In particular, the default rainbow map is:
(a) bad for color-blind users, a surprisingly large percentage of the population,
(b) bad because it artifically creates distinctions between regions while making it hard to judge real gradients.
(c) hard to use with the other color maps because they look similar but have different meanings.
However, there's not much alternative in Sim CFD at present... The greyscale color maps allow accurate visualization of realistic gradients, but are hard to see on neutral-colored backgrounds, and not very exciting. The thermal color maps are good but only for very specific uses.
There are a ton of resources on the web for explaining why rainbows are (usually) not appropriate
- classic: Rainbow Color Map (Still) Considered Harmful
- shorter: How The Rainbow Color Map Misleads
- target audience: Why Should Engineers and Scientists Be Worried About Color?
As well as good sources for generating and specifying useful color maps, and which is appropriate wil vary depending on the use (Color Brewer is popular). There are even ones that describe how to create a non-distorting disability-friendly rainbow (The Rainbow is Dead, Long Live the Rainbow!).
This seems like low hanging fruit and will keep people from turning to external software to do high value plotting of results.
I would like to be able to clone a results plane and/or copy settings from one plane to another. For example, if I had a plane set up with vectors, shading, etc. at X=0, then I could clone it align it with Y for a consistent look. Another use would be to make multiple cut planes (X=-1, X=0, X=1, etc) quickly with the same settings.
A similar idea I suppose could be applied to isosurfaces.
Ideally I'd like to have the surface meshing process to finish, even if it could not mesh a particular face, before the simulation aborts. So it could identify all surfaces with (mostly) too rough mesh sizes and put them into a geometry group which can finally be displayed and evaluated.
Would be nice to get more response from the startup process in case of "forgotten" settings, e.g.:
- for the use of gravity or compressed air you have to change to variable air
- Inlet has no temperature defined
Thought of something similar like the interactive diagnosis in Creo Simulate.