How can i make a CFD simulation

Project Support
1

Hello everyone,

I am having a problem simulating a wing profile (specifically the S1223). I simulated it in XFLR5, where I got a Cl value of approx. 1.23. But when simulating with CFD in Simscale, I got a value of 0.006, which seems a bit odd to me.

I tried following some instructions I found on the internet, but unfortunately it didn’t work.

Does anyone know of any good instructions that can be followed to perform a good CFD simulation for external aerodynamics?

The wing profile is an S1223 (cord line: 45 mm; AOA 4.7 degrees), which I generated using Fusion 360 and exported as a STEP or ITP file.

Wenn i have tried it sometimes the Mash or the Simulation itself doesn’t work.

Here are a few photos of my simulation:

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for the same Airfoil S1223 simulation from XFLR 5

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Thanks for helping me out

2

Hi @tzuehlkemem22, thanks for posting

Since I don’t have the project link, I can only guess what the problem might be. I would say it might be related to the reference area - keep in mind this is crucial for defining the drag and lift coefficients since it will be in the denominator for their calculation. Please check this resource:

Cheers
Igor

3

Hi @igaviano

here is the project link, could you take a look and tell me what I have done wrong

Thanks for helping
Timo

4

Hi @tzuehlkemem22, the reference area is certainly wrong, please check the resource I’ve shared earlier to get the actual area.

5

This was good advice, thanks for that

but know this Cl ist around 0.41, but of the simulation from XFLR5 it should be around 1 what else couldn’t be right?

6

Hi @tzuehlkemem22, a few points:

  1. You need to make sure you’re comparing apples to apples here. If the reference areas are different, of course you’ll get different values

  2. Keep in mind there is always some kind of error in CFD studies, so don’t trust them blindly. Many times where CFD shines brightest is when comparing different design iterations, not necessarily when retrieving the absolute values

  3. At the same time, you can get closer to the absolute values by applying refinements and running a mesh sensitivity study. This validation case tends to be very helpful:

Cheers
Igor