[mahdi_sangbori]

hello everyone
i am simulating naca 0012 with ansys fluent.
i am trying all of the turbulent models(like spallart,k-e , k-w sst , and transition sst models),the conclusion was that the best model is sst transition and k-w sst.
in transition sst model bubble is showed but in k-w sst it doesnt .
y+ in my calculating is below1 and i have used c-grid, bundry condition is that the left and bottom surface is the inlet and the straight right and upper surface are pressure outlet .
Re is about 8*10^4
i am simulating in low re numbers and M=0.023 v=8m/s.
i have got some problem
first of all i have no results that i can use them to valid my solution in this Re number .
the second problem is that(when i compare the solution of the theory wing section book i found out that the in range of reynolds number the Cl is the same at the Re number shown! in angle of 8 is about 0.8) when i compare my Cl that is 0.06 i found out that i have got some mistake


please help
sorry of my bad english

[edu_aero]

Originally Posted by mahdi_sangbori

hello everyone
i am simulating naca 0012 with ansys fluent.
i am trying all of the turbulent models(like spallart,k-e , k-w sst , and transition sst models),the conclusion was that the best model is sst transition and k-w sst.
in transition sst model bubble is showed but in k-w sst it doesnt .
y+ in my calculating is below1 and i have used c-grid, bundry condition is that the left and bottom surface is the inlet and the straight right and upper surface are pressure outlet .
Re is about 8*10^4
i am simulating in low re numbers and M=0.023 v=8m/s.
i have got some problem
first of all i have no results that i can use them to valid my solution in this Re number .
the second problem is that(when i compare the solution of the theory wing section book i found out that the in range of reynolds number the Cl is the same at the Re number shown! in angle of 8 is about 0.8) when i compare my Cl that is 0.06 i found out that i have got some mistake


please help
sorry of my bad english

Firstly, in order to compare it u can do it with a software called XFOIL (totally free), or by some aerodynamic numeric models. I have some on Excel and Matlab, but u should know the model in order to use it and change according to your neccesities.

Abour the Cl, it seems like the adimensionalization is not done correcty, have u checked it?

[mahdi_sangbori]

Originally Posted by edu_aero

Firstly, in order to compare it u can do it with a software called XFOIL (totally free), or by some aerodynamic numeric models. I have some on Excel and Matlab, but u should know the model in order to use it and change according to your neccesities.

Abour the Cl, it seems like the adimensionalization is not done correcty, have u checked it?

hi Eduardo
thanks for your response
Cl that i get is from here : report,forces, and the vector that is
Perpendicular to the velocity vector.am i right?
i dont know anything about xfoil and what you said for validation,would you please help me more about validation, in models that i have used,k-w and transition were better than other but transition sst was showing the sepration bubble and other models did not!
i am using steady state to calculating!

[edu_aero]

Originally Posted by mahdi_sangbori

hi Eduardo
thanks for your response
Cl that i get is from here : report,forces, and the vector that is
Perpendicular to the velocity vector.am i right?
i dont know anything about xfoil and what you said for validation,would you please help me more about validation, in models that i have used,k-w and transition were better than other but transition sst was showing the sepration bubble and other models did not!
i am using steady state to calculating!

Yes, perpendicular to velocity.


About validation, is quite tough, the program that I told u, may be u can dinf a tutorial on the Internet. It is only for Nacas and easy to used. And about the other... it is quite complicated if u haven't studied them in an Aerodynamics subject.

However, about the models, I can help u out. I was doing some simulations about the performances of a cycling wheel and used a paper called 'Ten Years of Industrial Experience with the SST Turbulence Model' (About SST Transition Model) and 'Improved Two-Equation k-omegaTurbulence Models for Aerodynamic Flows'.

U will find there everything that u need it

[mahdi_sangbori]

Originally Posted by edu_aero

Yes, perpendicular to velocity.


About validation, is quite tough, the program that I told u, may be u can dinf a tutorial on the Internet. It is only for Nacas and easy to used. And about the other... it is quite complicated if u haven't studied them in an Aerodynamics subject.

However, about the models, I can help u out. I was doing some simulations about the performances of a cycling wheel and used a paper called 'Ten Years of Industrial Experience with the SST Turbulence Model' (About SST Transition Model) and 'Improved Two-Equation k-omegaTurbulence Models for Aerodynamic Flows'.

U will find there everything that u need it

xfoil shows Cl=0.9640!

[edu_aero]

Originally Posted by mahdi_sangbori

xfoil shows Cl=0.9640!

Then look for your error, probably your choir is not 1m or something realted with adimensionalization.

About the y+ value, do the inflation operation on the Mesh and everything will be alright. Because y+ depends of the wide of the first layer

[mahdi_sangbori]

Originally Posted by edu_aero

Then look for your error, probably your choir is not 1m or something realted with adimensionalization.

About the y+ value, do the inflation operation on the Mesh and everything will be alright. Because y+ depends of the wide of the first layer

my chord is 0.15 m

[edu_aero]

Originally Posted by mahdi_sangbori

my chord is 0.15 m

and are u dividing by that lenght?

[mahdi_sangbori]

Originally Posted by edu_aero

and are u dividing by that lenght?

sorry i dont understand what you mean!
in xfoil?
Re number is calculated with this chord , should i import it ?
if you mean in ansys, i scaled there

[mahdi_sangbori]

hi every one
my problem solved with ansys help finally
thank you all