# [aspect-devel] boundary velocity function expressions

Payman Janbakhsh payman.janbakhsh at mail.utoronto.ca
Sun Oct 9 15:08:29 PDT 2016

```Hi,
I'm trying to implement the following for a 2D problem:

Set Prescribed velocity boundary indicators = left : function  ,  right : function

But get error when trying to give  Function expressions in:     set Function expression =
I have tried separating 2 velocity components with semicolon and separate function expressions with comma .
Example:
Left boundary function                  right boundary function
Set Function expression =             if(z>=1000 , 1, 0) ; 0           ,           if(z>=1000, -1,0) ; 0

I've tried many ways including below but all give errors or nonsensical velocity Glyphs:
Set Function expression =          left:   if(z>=1000 , 1, 0) ; 0           ,     right:      if(z>=1000, -1,0) ; 0
Set Function expression =           left =   if(z>=1000 , 1, 0) ; 0           ,    right=       if(z>=1000, -1,0) ; 0
Set Function expression =           (  if(z>=1000 , 1, 0) ; 0     )      ,       (    if(z>=1000, -1,0) ; 0 )
...

How can I separate multiple function expressions each for its corresponding boundary indicator ?

Thanks

Payman
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