use the same conditions, get different results simulated by WUFI Pro and WUFI 2D

[Sharon]

I expect you can help me to solve some problems during the simulations.
The construction layers from the outdoor to indoor are cement lime plaster (20mm), mineral insulation board (70mm), aerated concrete (200m) and cement lime plaster (20mm). Then assignment the climate data, initial conditions, etc.

Used WUFI Pro and WUFI 2D do the same simulation, but the result is just similar, not identical. You can see the results below the text. The green line is the simulation result of WUFI Pro, the purple line is the simulation result of WUFI 2D. We can see the purple line above of the green on all the time, I am in doubt of this phenomenon. So what is the reason for this phenomenon? Which line is closer to the actual situation?

[Christian Bludau]

Hello Sharon,
what is the graph showing? Apples, water content, RH? And at which position?
How many elements was the width of your construction?
What was your convergence criterion in 2D?

Generally spoken the results of 1D and 2D are the same, if the settings are the same.
If you use the same grid (can be adapted manually) in x-direction and just one or two elements in y-direction with a convergence criterion of about 1e-6 and have a look on the same position, the results are the same.
If you have a lower convergence criterion, more elements to the y-direction etc. the results will start differing between the two versions. Usually the moisture/rh will move away from each other faster and more depending on the exact position than the temperature.

Christian

[Sharon]

Thank you very much.
The second graph showing the RH of leftmost grid of Mineral.
The convergence is the same in 2D and Pro.
I re-edit the 2D model, making the elements in y-direction changed to 2; then the results are the same.
But I Still can not understand why the y-axis is divided finer, the result of relative humidity in 2D is generally biger than Pro?

[Christian Bludau]

Hi Sharon,

is the element you are looking at the same size in 1D and 2D?
As especially for moisture the right position and size is really important for comparing.

Christian