Handling water balance error in wet conditions

A discussion forum for users of the new HYDRUS 2D/3D. HYDRUS is a software package for simulating water, heat and solute movement in two- and three-dimensional variably saturated media. Happy Posting!
Post Reply
mGohar
Posts: 36
Joined: Wed Jul 15, 2015 11:16 pm
Location: USA

Handling water balance error in wet conditions

Post by mGohar » Thu Oct 24, 2019 1:31 am

Hi,

I noticed that when my domain gets close to the wet condition, Hydrus seems to trigger something which results in improving the water balance error. My question is if that's true, what Hydrus does change and what condition triggers this?

WBE_T.png
WBE_T.png (19.54 KiB) Viewed 164 times

Thanks

Jirka
Posts: 4801
Joined: Sat Mar 16, 2002 3:47 pm
Location: USA
Location: Riverside, CA

Re: Handling water balance error in wet conditions

Post by Jirka » Thu Oct 24, 2019 2:05 am

There is no special treatment of mass balances under wet and dry conditions. I would assume that this may be caused by boundary fluxes (that cause wet conditions) and which are in the denominator when calculating mass balance errors. J.

mGohar
Posts: 36
Joined: Wed Jul 15, 2015 11:16 pm
Location: USA

Re: Handling water balance error in wet conditions

Post by mGohar » Thu Oct 24, 2019 8:31 pm

Thanks for your reply Jirka, I forgot to mention that the problem is an axisymmetrical domain and water is added in every two hours with a constant flux value (for duration of ~3 min) for the entire simulation time. My first though was maybe Hydrus decreases the convergence tolerance which (I guess) you ruled it out.

mGohar
Posts: 36
Joined: Wed Jul 15, 2015 11:16 pm
Location: USA

Re: Handling water balance error in wet conditions

Post by mGohar » Sat Oct 26, 2019 12:26 am

mGohar wrote:
Thu Oct 24, 2019 8:31 pm
Thanks for your reply Jirka, I forgot to mention that the problem is an axisymmetrical domain and water is added in every two hours with a constant flux value (for duration of ~3 min) for the entire simulation time. My first though was maybe Hydrus decreases the convergence tolerance which (I guess) you ruled it out.
I would like to add that the problem description (similar influxes through the simulation run-time) may suggest that this water balance error behavior might not be due to boundary fluxes.

Jirka
Posts: 4801
Joined: Sat Mar 16, 2002 3:47 pm
Location: USA
Location: Riverside, CA

Re: Handling water balance error in wet conditions

Post by Jirka » Sat Oct 26, 2019 12:34 am

If you use recommended spatial and temporal discretization and iteration criteria, you should not have any problem with water flow mass balance errors. J.

Post Reply