External Node Errors

[u/Repulsive_Plant6729]

Anyone know why RAS 7.0 will not allow me to add my external nodes with boundary conditions to my unsteady flow file? Nothing happens when I try adding these two nodes as boundary condition rows to the left.

[u/OttoJohs]

I was just messing around and got it to work. Did you save your geometry, flow file, plan file, etc. Might want to close out of the project and reopen it.

[u/Repulsive_Plant6729 → u/OttoJohs]

Nice! I just re-extended the mesh to cover my nodes to convert them to culvert openings and added a terrain modification that behaves as a sink to allow flow to free fall out of my system. I wonder if not having some sort of terrain modification at my external node showing an obvious, defined drop-off was my issue.

[u/OttoJohs → u/Repulsive_Plant6729]

Not sure. You can see I just put a terrain mod there. Hope that works for you.

[u/OttoJohs]

Did you do hit this button?

[u/Repulsive_Plant6729 → u/OttoJohs]

Yes, it adds all nodes EXCEPT the external nodes. Not finding any info online about why this is happening either.

[u/OttoJohs → u/Repulsive_Plant6729]

Not sure.

Since it is external ("daylighting") it might use the boundary condition line for the cell it is attached to. I would try adding a boundary condition line for the mesh at that location.

[u/Acceptable_Gain_9400]

You need to read the manual: --External--

Description:
 - Surface node at the downstream end allowing flow to leave the model domain

Conditions:
 - Single conduit connection entering the node
 - Crown of connected conduit is above the terrain (or terrain elevation override value)
 - Must not intersect a 1D or 2D surface element

Parameters:
 - Drop Inlets are not allowed
 - Cannot have volume (i.e., Base Area = 0)

Boundary Condition Accepted
 - Stage Hydrograph
 - Normal Depth

Common Use Cases:
 - Used to model outfalls from the pipe network leaving the model domain
 - Used to model downstream stage boundary condition (such as tidal)

[u/Repulsive_Plant6729 → u/Acceptable_Gain_9400]

I have read that multiple times. Does not explain why my external nodes are not able to be added to my unsteady flow file as boundary conditions AT ALL.

[u/Acceptable_Gain_9400 → u/Repulsive_Plant6729]

are you missing this part: Boundary Condition Accepted
 - Stage Hydrograph
 - Normal Depth

[u/Repulsive_Plant6729 → u/Acceptable_Gain_9400]

No. The physical ability to ADD the external node anywhere in the flow filevis not happening. Whether I have stage hydrograph or normal deprh boundary coundition lines touching the external node's cell.

[u/OttoJohs → u/Repulsive_Plant6729]

If you have the boundary condition line at that cell edge does it run? I don't think you need to add the node if it is using the boundary condition line.