creating velocity inlet profile on star ccm+
i'm an italian student and i've some problems with star ccm+.
i need to create a velocity log law profile but i don't know how to compile a field function. i 've tried to create some function component and to assemble these on vector one with no results.
i add my attempts:
i've tried to introduce the z variable with $$Position
u(z) component definition:
v(z) component definition:
help me please
thanks a lot
In my ccm the z variable is "Position_2" and to use them I make $Position_2 :)
/edith says: Often the field function is only shown when you had "used" them in a scene, don't know why but I only have the "Position"-Vector, when I used the scalar displayer Position -> Laboratory -> Z, I have the field function Position[Z].
I hope it helps you.
I actually did something similar with a power-law profile based on a desired flow rate where I used several field functions to calculate Re, exponents etc.
If you are using a cylindrical boundary (e.g. a pipe) you might find it easier to define a local cylindrical coordinate system (placed in the center of the inlet) and then use
to calculate the velocity based on the distance from the center of this CS.
Consult the manuel regarding the details of the x, y, z of the cylindrical coordinate system.
Hope this helps a bit...
thanks very much at all
thanks very much at all!! :) i've solved my problem :p
i don't understand why, but starccm+ don't love number squared...and on my first expression i've digited ^2 and not the simple number result.
well! if you need to simulated a velocity profile for an atmospheric boundary layer, the best way is to write the log law in component like what i've do and to create a field function velocity where put the component expression.like this
[((0.164696691/0.4)*log(($$Position+5.32267E-05)/5.32267E-05)*0.866)+3.084 , -(0.164696691/0.4)*log(($$Position+5.32267E-05)/5.32267E-05)*0.5 ,0]
good luck at all :)
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