Hi everyone,
I am a new user of sfepy, i need it to compute the diffusions equations on a turbine blade. But i am a little lost with the boundary conditions. I have tried to impose some dirichlet boundary conditions on some points of the edges of the airfoil but it keeps crashing with exceptions. For example in my .mesh file i have this at the line where my point is defined
0.1 0.5 25 (x) (y)
So I have written this in the region definition
regions = { 'Omega' : 'all', 'point25' : ('vertices of group 25', 'edge'), }
I have tried before with :
refions = {
'Omega' : 'all',
'extrados' : ('vertices in (y>0.1) ', 'facet'),
'intrados' : ('vertices in (y<0)', 'facet'),
}
and it was giving resuls (it was only for test purpose)
I don't understand very well how to define the boundary conditions (and to be honest the hole configuration file despite the documentation)
So if somebody could help me, i would be grateful !
cordially,
Nicolas DELAN
Hi Nicolas,
On 04/27/2016 04:49 PM, Nicolas DELAN wrote:
Hi everyone,
I am a new user of sfepy, i need it to compute the diffusions equations on a turbine blade. But i am a little lost with the boundary conditions. I have tried to impose some dirichlet boundary conditions on some points of the edges of the airfoil but it keeps crashing with exceptions. For example in my .mesh file i have this at the line where my point is defined
0.1 0.5 25 (x) (y)
So I have written this in the region definition
regions = { 'Omega' : 'all', 'point25' : ('vertices of group 25', 'edge'), }
So the group 25 vertices are forming an edge, right? Then this should work. If this is a single vertex, use 'vertex' kind instead of 'edge', as the 'edge' region would be empty.
I have tried before with :
refions = { 'Omega' : 'all', 'extrados' : ('vertices in (y>0.1) ', 'facet'), 'intrados' : ('vertices in (y<0)', 'facet'), }
and it was giving resuls (it was only for test purpose)
I don't understand very well how to define the boundary conditions (and to be honest the hole configuration file despite the documentation)
For example, to impose Dirichlet BC u = 1 in the point25 region to a scalar variable u, do:
ebcs = { 'a name' : ('point25', {'u.0' : 1.0}), }
For more examples, check [1], if you have not done that already.
Does that help?
r.
[1] http://sfepy.org/docdevel/users_guide.html#essentialboundaryconditionsan...
Thanks you very much, i have succeed to launch a calcul.
But the results are not really acceptable.
I think i really don't understand the syntax of the boundary conditions. If i am right, the group is the nomber in the last column of the mesh file in the points definitions but when i launch the simulation, the hole domain is affected.
In fact, i need to impose a field of temperature on the edges of the airfoil, this is why i try to understand how to impose a temperature at one node of the mesh.
In fact, i don't find anything on internet about the syntax of the regions that are used to apply the boundary conditions.
Just some news on my research, i have finally found out how to impose the field of boundary condition using a loop. I have attached my test file.
Glad to hear that!
So you need to apply BCs by a function on the whole surface, right?
The same can be achieved using the 'vertices of surface' region selector, and defining a function for computing the BC values, as described in [1]  see the attachment.
r. [1] http://sfepy.org/docdevel/users_guide.html#id7
On 04/29/2016 01:50 PM, Nicolas DELAN wrote:
Just some news on my research, i have finally found out how to impose the field of boundary condition using a loop. I have attached my test file.
participants (2)

Nicolas DELAN

Robert Cimrman