User Forum of Software BASEMENT

FloKerk

User

Registered: 2015-05-19

Posts: 3

Boundary Type "wall" unknown

Hello everyone,

at the moment i am working on a multigrain sediment transport problem with BASEMENT. I am trying to define geometries in my mesh by using the stringdef-function and everything seems fine till the actual processing.

I have definded a string wich symbols a pillar. Under hydraulics i choose the boundary type wall, but if i try to start the simulation i get the following Error message:

-> The boundary type 'wall' is unknown.
-> Domain: Simulation stopped due to errors

Under the BASEMENT Input Reference i could not find a answer to this problem. But perhaps someone here in this forum has a hint how i could achieve my goal.
If i am trying to put some type of geometry into the mesh e.g. a pillar of a bridge or something simillar how do i have to define the boundary type? Do i have to " cut a hole" into the mesh and if so how do i bind the specific friction parameter to the "hole".

Best regards,

Florian

sajjad

User

Registered: 2014-10-01

Posts: 101

Re: Boundary Type "wall" unknown

you can define an obstacle by cutting a hole and then applying 'wall friction' to 'on' in friction block of the run file. However, as per my knowledge, this wall friction will also be applied by the model on other no-flow (wall boundaries) as well. Alternatively, u can locally refine the mesh at the point where the pillar is and increase the z-coordinate of the points lying on the periphery of the pillar.

FloKerk

User

Registered: 2015-05-19

Posts: 3

Re: Boundary Type "wall" unknown

Hello sajjad,

thanks for the reply. I have tested your suggestions and it helped me a lot with my original problem, but like always i encounterd another one.

I am trying to simulate a kolk in front of a pillar (pillar geometry = original problem), i have tested and run some simulations with the new mesh and different parameters but in no run a kolk is building up. My suspicion is that i made a basic mistake wich is hindering me, i just can´t figure it out. There is just no removal of bedload in front of my pillar. Could the problem be connected with the fact, that the "hole" has no definded bedload?

Best regards

Florian

Matteo Facchini

Developer

From: Trento

Registered: 2014-09-05

Posts: 281

Re: Boundary Type "wall" unknown

Hello FloKerk and sajjad,

first of all thanks to sajjad for the answer. The aim of the forum is also to share ideas and thoughts among the users, and to help each other. Good job!

@FloKerk: a comment on your first post: generally you cannot define a BOUNDARY inside your geometry. You can use a INNER_BOUNDARY, but there is no inner wall to define.

Moreover, I think that you cannot see the erosion in front of the pile, because this is a 3D effect, while you are running a 2D simulation. What you can actually see is the increase of speed around the pile, but I don't think you will see a proper pile-erosion effect.

Hope this helps!

Cheers,

Matteo