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July 31, 2023, 05:01 

#21  
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Quote:
I concluded that the cd value is not correct but the drag value is correct. Sphere radius:25cm freestream velocity:30m/s . In these conditions it calculates around 35N of drag which means a cd of around 0.3 should be the answer which is close to the experimental results. But the cd ansys calculates is much lover at around 0.01 . I think the problem is at this calculation ansys makes. I did another calculation with the same sphere but at a 0.3m/s freestream velocity and 5.5e03 N drag was expected. Resoults gave 5.2e03 N which is pretty close. I will try to find the couse of the incorrect cd calculation but at that point it is not as important since the drag force values seems correct and ı can calculate the cd myself. Here is the mesh file you asked for https://file.io/yfFcUX9iOhpQ Thanks for your help 

July 31, 2023, 08:09 

#22 
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Lucky
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So.... did you check the reference values?
So now you understand why we asked for raw drag forces 

July 31, 2023, 08:42 

#23 
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July 31, 2023, 09:10 

#24 
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Lucky
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So what are the reference values......? If the drag force is correct then the only thing that can be wrong are the reference values. Surely, everything can't be right!


July 31, 2023, 12:47 

#25 
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Arjun
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October 11, 2023, 21:07 

#26  
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jinhoon park
Join Date: Oct 2022
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Quote:
Hello, I am also analyzing to find the drag coefficient of a sphere, but at re=400000, the drag coefficient does not come out as 0.1 but as 0.4. This is a very high figure. So I'm curious What turbulence model did you use and what cfd program did you use? And can you tell me what the range of y+ is? Oh, and did you use Structured when working on the mesh? Or did you do it with Unstructured? 

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coefficent of drag, drag, wrong results 
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