## Forcing the two ends of a channel (curvilinear grid)

MOHID Water forum. Questions and discussion around MOHID Water
david.blanquer.lde@gmail.com
MOHID Beginner
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Joined: Thu Jan 01, 1970 00:00

### Forcing the two ends of a channel (curvilinear grid)

Hi Mohiders,

I’m currently working on a domain with the sea, a pond and some channels that ensure the communication between the sea and the pond. This large domain is my coarser grid.
The goal of my work is to study the channels so I have generated a curvilinear grid representing only this area. This is the son’s digital terrain.
The son’s domain has two open boundaries, one on the sea and the other one on the pond.

As I can’t nest a curvilinear grid, I would like to impose manually to the son’s boundaries the waterlevel and velocities computed in a simulation on the coarser domain.
The issue is that I want to impose different conditions on each boundary (because the key element is the difference of waterlevel between the sea and the pond) and I don’t know how to do it.

Is there a way?

Best regards

David

paulo.chambel@hidromod.com
Posts: 117
Joined: Thu Jan 01, 1970 00:00
Location: Lisbon
Contact:
Davis,

you have at least two options.

The most simple:

1 - run a model with close boundaries. You need to define for each of the boundaries a discharge. Basically this is the approach follow in \"laboratories\" where you impose discharges in each of the \"channel\" side. You can generate a consistent flow with this kind of approach;

2 - use a flow relaxation approach where you relax near the boundary the model solution for the water level and velocity you want to impose in the open boundaries. This approach is more complex and you need to have a clear notion of all the problems that can be associated with open boundary conditions.

Paulo
The peace be with you