[Edward1]

Hi everyone,

I'm currently trying to model a channel with time-dependent boundary condition. it means that I want to make some of the walls move (with a sin(w*t) function for instance). It is suppose to model normal external forces that will improve mixing efficiency inside the close-channel. (you can see it on the picture, maybe it will be easier to understand)

I already have the geometry, physics models and so one. Moreover, I've read that I can use Tool->Motion->Morphing to do this kind of stuff (even if I still don't know how to use it ).

However, this morphing can only be applied on a "region", and not on one of the boundary. Consequently, I've tried to separate my surfaces into 2 regions (one for the moving walls, one for all the others). But then, both of them are not longer closed, and so I can't mesh them (even with the "Surface Wrapper").

Have you any idea to handle this problem? (and some advice to make the walls move after that?)

Hope it is clear enough,
Thank you in advance,

Edward

Ps : I'm sorry if my english is not perfect.

[ggulgulia]

Hello,

for all I know, morpher can indeed be applied to a single boundary. I suggest you to recheck the options in CCM+ window carefully.

1. Select the boundary patch you want to apply morpher to.
2. Go to physics condition under the particular boundary
3. Under motions, select Morpher.

There will be other options for controlling how the morpher behaves, which you will have to cross check.

Hope this was helpful

[Edward1]

hi,

Thank you for you answer.
Actually, I know how to set the 'motion' to a specific part. But in that case, if I want to do so, then I have to define two parts. One with the moving wall, one with the others surfaces. Consequently, both of them no longer define closed-surfaces which means I cannot build a mesh.

Maybe there is another solution to model moving walls (such as define normal stresses or momentum for each wall, but I am new on CCM+ and I don't know how to do it neither.)

[marmot]

it is all one part, thus a closed surface, you just have different surfaces within your 1 part and for these different surfaces you have moving or non-moving walls.

For the region / part you have the morpher on, when going to boundaries you can select different options, free, fixed, etc.

[Edward1]

Does it mean that I can define (with a table or something else) one motion for a particular surface and fixe the others surfaces (all of them belong to the same part)?
In that case, do you know what is the best solution to generate such table ? I know that 'table(xyz, time)' are available but I don't know how to fill it.

In any case, thanks a lot for your help

[marmot]

Yes you have 1 part with different surfaces, these surfaces point to different boundaries in your region.

You can do Table(time) or maybe easier is a field function, but lets say you choose displacement or grid velocity, you have to input a vector but perhaps to make things easier for you choose method "composite", now you have input for x,y,z, maybe two of them are 0 and for only 1 you need a table (time) or field function

for a table just create a simple csv file, have a header,
time, move
0,0
1,0.1
2,0.2
3,0

save a csv,

sccm+ will use a linear interpolation between values,

[Edward1]

That sounds perfect. I was looking at table(xyz, time) that look like
X Y Z displacement(t=0) displacement(t=0.1) ...displacement(t=t_end)
but I will have a look at the other tables that you suggest. I'll try it asap (because atm I have others issues )

Just another question : I will probably use a periodic boundary condition on these walls (to model vibrations, with sinus-like functions or something similar). Do you know if there is something else to do or if after sccm+ has reached the last value (t_end in my example above) it returns to t=0 and read values again and again?