[sadjad]

Hi
In CFX , when we write an expression, do need dimension is written?
for example : Den*g*(0.5[m] -y) or 1000 [kg m^-3]

And need locate or put SPACE between values and dimension or not?
for example : Den*g*(0.5[m] -y) or 1000 [kg m^-3]

what mines [.....]

How write an expression?

[Opaque]

Let us say this is your expression set

LIBRARY:
  CEL:
     EXPRESSIONS:
        MyDen = 1000 [kg m^-3]
        MyBuoyForce = MyDen * ( 0.5 [m] - y ) * g
     END
   END
END

I always space my [ .. ] by one space from the preceding value, as well as between items in the expressions. Never failed me.

Keep in mind that a given expression, such as MyDen, it is not only the value but its dimension as well; therefore, when you reference it somewhere else you only refer the variable name and not its components (value or dimensions)

[sadjad]

Thanks Opaque.

My expression is according below but it dosnt answer me :
What is my error?

Den : 1000 [kg m^-3]
InPress : Den*g*(0.5[m] -y)
WaterX : 1 [m]
AirVF : Step((x-WaterX)/1[m])
WaterVF : 1-AirVF

and , in Global Initialization > Fluid Settings , when type "WaterVF" or "AirVF" ,cfx give me error and wants numerical value and dosnt accept "WaterVF" or "AirVF"

[Antanas]

Originally Posted by sadjad

Thanks Opaque.

My expression is according below but it dosnt answer me :
What is my error?

Den : 1000 [kg m^-3]
InPress : Den*g*(0.5[m] -y)
WaterX : 1 [m]
AirVF : Step((x-WaterX)/1[m])
WaterVF : 1-AirVF

and , in Global Initialization > Fluid Settings , when type "WaterVF" or "AirVF" ,cfx give me error and wants numerical value and dosnt accept "WaterVF" or "AirVF"

What kind of error? What is range for x?

[sadjad]

my range of x=1 m

[Opaque]

Your example uses : instead of =. Is that correct ?

[sadjad]

my x value is 1
ok ?

[Antanas]

Originally Posted by sadjad

my x value is 1
ok ?

And the error is.... ?