CFD Online Discussion Forums

CFD Online Discussion Forums (
-   CFX (
-   -   sine funtin (

kmgraju August 20, 2010 00:58

sine funtin
I am doing ansys CFX analysis inside the human artery .There is a systole and diastole flow inside the artery. How to define the velocity profile as an inlet. I have to define the velocity profile as a sine function
u(t)= Uo( 1+sin (4*pi -Pi /2)
How to set this boundary condition . I dont know the procedure . I kindly request someone to help me to set the boundary condition step by step.

Thank you in advance


Turbomachine August 20, 2010 03:19

boundary conditions
CFX employs the CEL language where you can define expressions. Under the expression tab create a new expression and define the velocity profile in the form you have with reference to global coordinates. Then under the boundary tab set the value of the boundary to the defined expression.

It looks like a 1D analysis so set the other to components of velocity to zero. What does the independent variable t mean in your formula?

kmgraju August 21, 2010 09:25

1 Attachment(s)
Thanks for your reply

I have written the expression in the following format
Umax+Umax*sin(4*pi*Frequency*t -pi /2)

Is this correct. I try to calculate the expression value , The value becomes zero.
how it is possible . anyhow I have to get my Umax if sine value is zero. But the value I am getting is zero why?

NickFL August 21, 2010 10:41

1 Attachment(s)

Try using this:

Umax+Umax*sin(4*pi*f*t -pi /2)

where f is your frequency define in another expression.

Frequency is a CFX built in variable and you do not want to use it for your expression.

kmgraju August 21, 2010 11:04

Dear NickFL
Thank you very much for your kind advice . I got it.

All times are GMT -4. The time now is 08:15.