2d-Bridge and culvert modelling

[Anonymous]

Hi

I’ve been developing a 2D HEC-RAS model and am having stability issues.

The floodplain I am modelling at the moment consists of a bridge and a culvert bisecting the catchment. I’ve tried the following modelling approaches in accordance with the examples provided.

1. 1D upstream- 1D bridge – 2D downstream – Stability issue at the connection between 1D and 2D components
2. 2D upstream -1D bridge – 2D downstream – Stability issue at the connection between 1D and 2D components
3. 2D upstream and downstream without bridge/culvert – works fine.

How would you model a 1d component within 2d floodplain? And how would improve stability at the 1d/2d connection?

I look forward to hearing from you soon.

Kind Regards
MK

[cameron]

Using the 1D/2D iteration options can help (page 91-92 of user 2D user manual) has some good information working with 1D and 2D connections.

You may need to add more elements in the vicinity of the 1D structure. If the model is going unstable right away you may need to do a hotstart/warm up in the 2D domain.

Included in one of the test cases that comes with the data is an example of a 1D structure in a 2D domain.

I would also check what time step you are using as this has a big impact on if it is stable or not.

[Author]

Posts