[shash]

hi,
I am new to openfoam, i need to set initial pressure field as function of height.
i donot want to use setfields (uses third party software) to get the task done, can i use internalField nonuniform <List>; //but donot know how to set the list??

[gschaider]

Originally Posted by shash

hi,
I am new to openfoam, i need to set initial pressure field as function of height.
i donot want to use setfields (uses third party software) to get the task done, can i use internalField nonuniform <List>; //but donot know how to set the list??

setFields is not third party. But it won't set the type of field you want

Setting that list can be done by hand using a text editor (but it is not practical ), by writing your own utility in C++ or using funkySetFields which is third party software

[Mojtaba.a]

Originally Posted by gschaider

setFields is not third party. But it won't set the type of field you want

Setting that list can be done by hand using a text editor (but it is not practical ), by writing your own utility in C++ or using funkySetFields which is third party software

Dear Bernhard,
is funkySetFields utility capable of setting a list of cells within a complex region?
by complex region I mean not to be a common shape like rectangle or circle. is it possible to define user defined regions to select particular cells?

Thank you,
Mojtaba

[gschaider]

Originally Posted by Mojtaba.a

Dear Bernhard,
is funkySetFields utility capable of setting a list of cells within a complex region?
by complex region I mean not to be a common shape like rectangle or circle. is it possible to define user defined regions to select particular cells?

Thank you,
Mojtaba

If you can define the region by an expression (in terms of coordinates or other fields) ... you're in business.

If the complex region is written to disc as a cell zone or a cell set ... you're in business (but I think setFields can handle that too)

If it is defined as a mixture of the above ... you're in business.

Bottom line: you've got to be more specific about what you mean with "complex"

[Mojtaba.a]

Originally Posted by gschaider

If you can define the region by an expression (in terms of coordinates or other fields) ... you're in business.

If the complex region is written to disc as a cell zone or a cell set ... you're in business (but I think setFields can handle that too)

If it is defined as a mixture of the above ... you're in business.

Bottom line: you've got to be more specific about what you mean with "complex"

Thank you Bernhard,
well in my case, by complex I mean a region which is surrounded by multiple straight line borders.
For instance this simple region, which is surrounded by these lines:

y=-x+1
y=0
x=0

Thank you

[gschaider]

Originally Posted by Mojtaba.a

Thank you Bernhard,
well in my case, by complex I mean a region which is surrounded by multiple straight line borders.
For instance this simple region, which is surrounded by these lines:

y=-x+1
y=0
x=0

Thank you

Well. If a triangle is your idea of complex ....

That can be easily done with a condition like this in funkySetFields:

(pos().y>0) && (pos().x>0) && ((pos().x+pos().y)<1)

Either you use it in a condition if you want the rest of the field unchanged

funkySetFields -time 0 -field alpha -keepPatches -expression "1" -condition "<cond>"

or you reset the wholde field

funkySetFields -time 0 -field alpha -keepPatches -expression "<cond> ? 1 : 0"

(for <cond> insert the above expression)

[Mojtaba.a]

Originally Posted by gschaider

Well. If a triangle is your idea of complex ....

That can be easily done with a condition like this in funkySetFields:

(pos().y>0) && (pos().x>0) && ((pos().x+pos().y)<1)

Either you use it in a condition if you want the rest of the field unchanged

funkySetFields -time 0 -field alpha -keepPatches -expression "1" -condition "<cond>"

or you reset the wholde field

funkySetFields -time 0 -field alpha -keepPatches -expression "<cond> ? 1 : 0"

(for <cond> insert the above expression)

Thank you Bernhard,
This really helped.
I have an another little problem. I want to set z0 values (roughness parameter) for this particular region. as you know z0 is not a field in OF like U or p. well you know these better than me
Do you have any idea how I can set values for it?
in nut file I have something like this:

ground
{
type nutkAtmRoughWallFunction;
z0 $z0;
value uniform 0.0;
}

Can I use funkySetFields for setting the values of z0?

Thank you

[manu551]

Originally Posted by gschaider

If you can define the region by an expression (in terms of coordinates or other fields) ... you're in business.

If the complex region is written to disc as a cell zone or a cell set ... you're in business (but I think setFields can handle that too)

If it is defined as a mixture of the above ... you're in business.

Bottom line: you've got to be more specific about what you mean with "complex"

Hello,

I'm in the second case and I've got a cell set, but the problem is how to assign two different costant values for two different regions... How can I set internalField initial value dictionaries of variables?

Thanks

[gschaider]

Originally Posted by manu551

Hello,

I'm in the second case and I've got a cell set, but the problem is how to assign two different costant values for two different regions... How can I set internalField initial value dictionaries of variables?

Thanks

Assuming that you have the field foo, want to preserve the boundary conditions and you have two cellSets set1 and set2 which you want to set to 42 and 666 then you could do it with funkySetFields like this

funkySetFields -time 0 -field foo -keepPatches -expression "set(set1) ? 42 : (set(set2) ? 666 : foo)"

I think it is also possible with setFields but for some reason on machines that I use mysteriously an installation of swak4foam appears and then the tempatation to use funkySetFields is overwhelming