[didoman0]

Check the comment please

[didoman0]

Hello Everyone !
I need help in an issue.I was doing flow analysis to get the cd of a car design but i noticed that the values isn't realistic at all as the i get values of 6.2272e-03 which means 0.006


so i made the same steps on a cube to make sure that i do the right steps so if i make the right steps i should get 1.15 for the cd where i got the same non realistic values the value was 4.8301e-04 which means 0.0004



So i dunno what is the wrong that i do that give me those values,
My steps to do the analysis is :
1.Getting the Fluid Flow(Fluent)
2.Importing the Cube or The Object that i would like to make the analysis on
3.Making Enclosure
4.Making Boolean and subtract the enclosure from the object
5.Defining the name selection of Inlet , Outlet , Wall and finally the object
6.Closing Geomtry and Opening Mesh
7.Generating Mesh and then changing the Relevance to -100 from Defaults
8.Closing Mesh and Updating Project
9.Opening Setup
10. General: Solver Type:Pressure-Based
Velocity Formulation: Absolute
Time:Steady

11. Model , Choosing: Viscous-Laminar
12. Materials: Air
13.Boundry Condition , Inlet --> Edit ---> Specification :Magnitude , Normal to Boundry
Velocity Magnitude: 122m/s

14.Reference Value: from the inlet
15.Solution Method: Coupled --> Least Square , Second Order

16.Montoring the cube cd and cl , Values : 1

17.Solution Intialization , Hybrid then i press Initialize

then Run Calculations 500 Iteration

then getting those values





I use Ansys 17.0

I am trying to get the cd and lift of the object

If anyone notice anything wrong , tell me please as i am working on that issue for long time and can't configure what is wrong , Maybe i don't do something specific in the Meshing step ?

Thanks in Advance

[ryariyaz]

Have you checked the quality of mesh and scaling factor of mesh. One approach is that scale your mesh and try again

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[didoman0]

Originally Posted by ryariyaz

Have you checked the quality of mesh and scaling factor of mesh. One approach is that scale your mesh and try again

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Can you give me more details please ?
What should i do , What should i modify ?

[ryariyaz]

In solver there is setting for mesh scaling factor check it. I think it will do

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[ryariyaz]

I guess you problem is because of mesh were created in someother unit and solver takes it in SI unit so check meshing scaling i think it will work and you get a realistic value

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[didoman0]

Originally Posted by ryariyaz

I guess you problem is because of mesh were created in someother unit and solver takes it in SI unit so check meshing scaling i think it will work and you get a realistic value

Sent from my Redmi Note 4 using CFD Online Forum mobile app

Here are my settings

http://imgur.com/a/S3WhL


The cube is 20m x 20m x 20m