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# Simulation CFD

#### How to properly create graphs?

268 Views, 7 Replies
01/06/2018 5:32 PM

Forgive me if this has been discussed before but I need to figure out how to select the type of graphs I want, and how to create graphs without individually selecting points. I have my project files down below and would like to look at some data that differs between the different designs to determine which design would be better.

Visualization is a neat option that I will use but I'd like to have graphs and visualizations together.

P.S Are there any options to help me determine the turbulent flow? I tried using the Wall Calculator and looked around but couldn't find any options.

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#### Re: How to properly create graphs?

01/06/2018 6:04 PM

One more question. I have two slightly different models I want to experiment on and I have set everything equal to each other (Materials, Inelts, Outlets, Boundary Conditions, ect) but whenever I look at the Planes tab the two look very different. Any ideas?

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#### Re: How to properly create graphs?

01/06/2018 10:04 PM

One more thing (Probably the most important part that I thought of)...

Does CFD tell me the total force on the grid fin due to the airstream/ The total moment of the fin due tot he airstream? If not, what programs could tell me this?

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#### Re: How to properly create graphs?

01/08/2018 9:31 AM

Hi @ahKN6TH,

You should consider using the decision center! This lets you compare designs using images and plotted results. Here is an article and a webinar on the subject. XY plots will give you graphs of any result quantity over a selected distance.

Q: Does CFD tell me the total force on the grid fin due to the airstream/ The total moment of the fin due tot he airstream? If not, what programs could tell me this?

A: You can achieve this using the wall calculator as described here.

Q: Are there any options to help me determine the turbulent flow?

A: You can select some turbulent flow factors e.g. Turbulent Kinetic Energy and Turbulent Intensity in the result quantities tab before hitting solve.

All the best,

David

David Short
Technical Support Specialist, Simulation
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#### Re: How to properly create graphs?

01/08/2018 10:12 PM

Thanks! I am trying these options as I am typing this.

One more if you dont mind though.

(Taken from the External Compressible Flow guide).

Does the part highlighted in yellow indicate that is the minimum and maximum range to find the reference pressure? If so, what should I do if I need to simulate something at a much higher altitude (86km to be precise)?

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#### Re: How to properly create graphs?

01/09/2018 12:39 AM

Scratch that, I figured that one out.

I have one problem running the simulation. I have a model that I want to see interacting with the air at supersonic speed (Mach 8)  and created a pretty big wind tunnel via Geometric Tools tab on CFD (To prevent any unwanted interactions between the air flow of the model and the walls by multiplying length/width by 20)  and it seems as if the velocity has slowed down from 2744m/s down to about 400m/s by the time it reaches the model.

How can I have the air go Mach 8 throughout the entire wind tunnel (In other words, how can I make sure the air stream is about Mach8 when it reaches the model)?

I have tried a solution for this by giving the input velocity and pressure and output as Unknown, velocity (but pointed outwards), and pressure. I don't know if this is the correct way to solve this

Thanks

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#### Re: How to properly create graphs?

01/09/2018 8:53 AM

Hi @ahKN6TH,

Please can you start a new thread for this new topic as it will help people with a similar problem to find it.

Also attach a .cfz support file to your post in the new thread then i can take a look at your setup and hopefully offer some suggestions.

Thanks,

David

David Short
Technical Support Specialist, Simulation
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