User Forum of Software BASEMENT

sajjad

User

Registered: 2014-10-01

Posts: 101

Discharge calc. normal to a stringdef

Dear friends,

I would like to know how the discharge normal to a stringdef is calc. in basement (given unit Q, the primary output of 2d SV model). In basement, the stringdef definition requires connectng nodes. In certain situations, we require discharge crossing a section normally, but in case of a unstructured mesh, we cannot  prescribe a section normal to the flow direction because the nodes are not normal to the flow direction, instead, the stringdef may be a zig-zag line. If we know the formula by which discharge normal to an edge is calculated then we can multiply the discharges with unit normal of the section across which ew want to compute the discharge. If possible also make this info part of the doc. manual.

Regards

Lukas Vonwiller

Developer

Registered: 2014-09-04

Posts: 127

Re: Discharge calc. normal to a stringdef

Hi Sajjad

In the case of hydraulic discharge, we simply add all discharges over all edges (defined between two nodes) of the stringdef.
I recommend you to define these cross section as breaklines in your mesh. This way you have a straight line, and discharges over these edges are well defined.

I hope this helps!
cheers,
Lukas

sajjad

User

Registered: 2014-10-01

Posts: 101

Re: Discharge calc. normal to a stringdef

Thank you for your reply. It is very helpful.

A question about 'balance momentum fluxes'. Can i characterise the 'x balance momentum term'   as 'rho*U*A*U/rho' because its units are [m4/s2] (same as given in the basement manual) U is velocity in x-direction, A is the area of the edge normal to the x-direction and rho is mass density [kg/m3]?

Regards

Lukas Vonwiller

Developer

Registered: 2014-09-04

Posts: 127

Re: Discharge calc. normal to a stringdef

Hi Sajjad

Could you please open a new topic for this question?
The reason is that it doesn't mach with the topic title, and therefore will not be found by users searching for these keywords.
Furthermore I don't really understand your question, please specify your question a little bit, thanks!

Best regards
Lukas