User Forum of Software BASEMENT

jakobs

User

Registered: 2023-06-08

Posts: 3

Error in mass balance of Controlsections and total change of volume

Hello,
I am facing the following issue:
I have a morphodynamic simulation of an instationary flood wave and I want to evaluate the transport capacities and the aggradation and erosion process.
Unfortunately, the inflow/outflow and control section transportrates do not fit together with the change in elevation values (delta_z) and total change in volume.

Inflow: 47490 m³
Controlsection_1: 33095 m³
Controlsection_2: 39874 m³
Controlsection_3: 37514 m³
Controlsection_4: 38827 m³
Controlsection_5: 38372 m³
Outflow: 37594 m³

Just from looking at the Inflow and Outflow, I'd assume that the total difference in volume should be around +10000 m³ * (1/(1-p)) = 15873 m³, for p=0.37.
However, if I look at the delta z values of the mesh and calculate the total difference in volume by hand I obtain 2209 m³, which is the same value I obtain from SMS (so I guess it is correct). Another point what makes me very sceptical is that between Inflow and Controlsection_1, I'd expect big aggradation since the transported material differs by 14000 m³, but there is nothing noticeable going on...
Is there an obvious reason why these values are so different? I've read that the controlsections do somehow interpolate some Q_sed values but is the difference really that big?
My upstream boundary condition is set to “transport capacity” and my downstream boundary is set to “IODown”.

Best regards,
Jakob

Matthias Bürgler

Developer

From: Zürich

Registered: 2019-04-04

Posts: 175

Re: Error in mass balance of Controlsections and total change of volume

Hi Jakob,

Did you figure this out or is this is an open issue?

Best regards,
Matthias