Jump to content
TUFLOW FV
Sign in to follow this  
Guest Chris Nielsen

How do structures in TUFLOW FV handle submergence?

Recommended Posts

Guest Chris Nielsen

Could you briefly explain how FV handles weir submergence? I didn’t see it in the last draft version of the user’s manual we’ve got.

Share this post


Link to post
Share on other sites
Guest Chris Nielsen

Structures are handled in a way so that we switch from the full momentum equations to the structure equation. This takes care of submergence issues and also stability problems, especially if (for whatever reason) the structure equation is not a constriction to flow (ie an inadvertent user error).
 
The logic process for computing structure flow is as follows:
1       At the commencement of a model timestep, the structure flow (or, specific to a weir, the weir free overflow) is calculated (Qstruc) and also the standard shallow water equation flow is calculated (QSWE).
 
2       A check is performed between the structure flow (Qstruc) and that calculated using the Shallow Water Equation (QSWE), where:


Ø  IF Qstruc < QSWE THEN

o    Apply Qstruc to cell face

Ø  ELSE

o    Apply QSWE to cell face (ie ignore the structure)

 

3       If Qstruc is applied then momentum is transferred through the structure based on Qstruc and upstream velocity, which is appropriate for a weir.
 
To give you an example of how this works OK, I’ve attached a paper that Bill wrote a while back (see link) – I replicated the test that is shown in Figure 8 of this paper (see attached graph). As you can see, we get a near perfect match with theory and TUFLOW Classic results at all stages of flow regime.
 
 

post-5-0-84421500-1394162308_thumb.png

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
Sign in to follow this  

×
×
  • Create New...