Hi,
I am attempting to model a flemish bond brick wall with lime mortar in it and an internal lime palster.
Everytime I run though, it always seems to come to a point where the MC of the whole construction suddenly jumps to 100% ish...
The time point varies but is always associated with rain in the weather file.
I have put the grid to fine in both directions, manually made it even finer, and then coarser to see, tried differing the internal and external environments (different weather files), run with accuracy increased and adapted convergence on, changed the initial conditions, mositure loads, internal temperature and so on, but to no avail, every run at some point in the first month or so the whole wall suddenly fills with water in one or two time steps.
It runs fine without the MC on but fails with the MC on and after the walll has suddenly filled with water the calculations carry on but are much more rapid, needing less than 10 iterations for the majority of time steps.
In one four year run, the MC not only suddenly increased it also suddenly decreased after 3 years and then suddenly increased again, as it went into year 4 at the same point as when it had in year 1.
Rainwater absorption in on 0.7, and the external wall is unprotected brick work and lime mortar joints. All the materials are from the database and have hygric extensions that seem fine.
In the help files I did read that small mortar joints can lead to problems of over estimation of the moisture flow between the brick and mortar and that a 1mm layer should be added with an appropriate value for the liquid water mositure transfer facotr as this may be conisderably reudced at the brick mortar interface in reality, however the help file doesn't say what to set the 1mm layer factor too, and is it a 1mm of the standard mortar with the value changed or like a 1mm air gap? and does lack of this 1mm layer addition explain the sudden filling of the wall with water that I'm finding?
Can anyone help?
Problem_with_MC_running
I'm not sure i've understood very well your problem, as i'm quite a new user of WUFI, but I think i had a similar problem, a saturation phenomena always associated with rain in the weather file. And this is the space to share problems, so maybe it can help ?
In my case, the Water content was jumping to a saturated value, and the calculation stopped, unable to carry on.
The material I used was the SandStone Posta, from MASEA Database, and it has a high water absorption coefficient (0,25 kg/m²s^0,5 ). I think this is one of the origins of my problem.
To solve that, i made two modifications :
- the moisture storage function has a sudden change, just before the saturation. I ticked the box "Approximate" to "smooth" it
- i put the DWS coefficient to 0 after saturation, to "stop water absorption if the material is saturated : the transport doesn't stop, but there's just no more "additional absorption".
With these settings, i solved my problem of water absorption by forcing WUFI to do the calculation and i have now correct results.
Maybe it won't help you, but check if your problem is not just due to hygric properties of your material
In my case, the Water content was jumping to a saturated value, and the calculation stopped, unable to carry on.
The material I used was the SandStone Posta, from MASEA Database, and it has a high water absorption coefficient (0,25 kg/m²s^0,5 ). I think this is one of the origins of my problem.
To solve that, i made two modifications :
- the moisture storage function has a sudden change, just before the saturation. I ticked the box "Approximate" to "smooth" it
- i put the DWS coefficient to 0 after saturation, to "stop water absorption if the material is saturated : the transport doesn't stop, but there's just no more "additional absorption".
With these settings, i solved my problem of water absorption by forcing WUFI to do the calculation and i have now correct results.
Maybe it won't help you, but check if your problem is not just due to hygric properties of your material