WUFI

Hello

I simulated the water absortion of a wall with 40cm of thickness and 2m high using WUFI 2Dv2.1 and WUFI 2D 3.3. I simulated for 1 year and took pictures at the same day and same hour of the 12 months of the year. The results obtained should be similar, although as you can see in the word file inside the link below the results are very different. This link contains the word file, the files used in both WUFI versions and the exterior climate file. LINK: http://feupload.fe.up.pt/get/iQC2b0qmUumJCHl

I used the same climate file for the exterior surface, the same material and the same interior climate. I selected adiabatic in north direction on both versions of WUFI. In south direction I used 101% of relative humidity in WUFI 2Dv2.1 and 100% in WUFI 2D 3.3.

Any ideas about what's wrong?

Thank you for reading and trying to help me.

Hello jdelegado,

if I remember right, Wufi 2D 2.1 was not able to calculate with rain on the outer surface. So to get the same results, switch the Rain Reduction Factor at Oeste to 0. Further the 100% RH you used in Wufi 2D 3.3 is not the same like the 101% in Wufi 2D 2.1. 101% means, that there is always water for sucking available, the moisture storage function is at super saturation level. With 100% relative humidity you only reach the free saturation, which is lower. So what you should do is to create a climate file for this boundary condition (sul) which contains enough rain every hour. Therefore use the createclimatefile.xls and create a kli file.

Christian

Thank you for your quick reply.

I made the changes that you adviced me to do and I created a kli file following the instructions in WUFI 2D 3.3 help. I created a file with one line exactly the first line that you can see in picture below (I just switched the number of hours to 8760).



This picture was taken from WUFI help and there is an explanation for rain load load values but I still have some doubts. What kind of values are reasonable for each material?

I simulated again but still exists some differences namely:

-The height of water obtained in 2 versions is different (higher in WUFI 2D 3.3)
-Relative humidity profile is different

Hello,

why don´t you use the kli file from 2D 2.1 for 3.3 as well? The way you are doing this at the moment, you have different conditions on the surfaces. With the kli-file the radiation is measured, so the values is used direct on the surface while using the wac file the amount of ISGH is calculated for the orientation and inclination. Try to use the kli-file for the 3.3-simulation as well.

The way you created the kli-file for the suction is right, but the temperatures are different because using only one time-step you do not express the sinusoidal temperature you used in Wufi 2D 2.1. You should create a kli-file with hourly values or at least 24h to express your temperature.

Regarding to the rain you can use as much water as you like. The absorption depends on the material, so if there is more water than can be absorbed, it is canceled.

Please make sure, that all your boundary conditions are the same before doing your comparison between the old and the new 2D.

Both your points:
-The height of water obtained in 2 versions is different (higher in WUFI 2D 3.3)
-Relative humidity profile is different
may be related to a different temperature field in your construction. As the temperature is one of the driving potentials, you have to make sure, that the temperature fields are the same as well. The result should be the same for both versions. But if there is a difference i would tend to trust the actual version . We made many tests validating it.

Christian

Hello again

After your last post I obtained practically the same results in both versions of WUFI. Although, now I'm with another problem. When I select rain reduction factor to 0.7 on exterior surface I obtain the results below:




But, when I switch it to 0 I obtain this:



I'm using a .wac file. How can this be so different? Which situation is closest to reality?

Furthermore I'm trying to colect information about Relative Humidity and Water Content at 1,7m high. I created a thin layer at approximadetly 1,7m as you can see in the picture below.




When I want to get the results if I select the rose element as in picture below Am I doing this right?




I inserted another material in WUFI database but when I try to simulate WUFI gives me this error:



Any ideas about what's wrong?

Thank you for reading and trying to help me.

<
<After your last post I obtained practically the same results in both versions of WUFI. Although, now I'm with another problem. When I select rain reduction factor to 0.7 on exterior surface I obtain the results below:
<
<But, when I switch it to 0 I obtain this:
<
<I'm using a .wac file. How can this be so different? Which situation is closest to reality?

The rain reduction factor controls the fractional part of the rain which should be available for suction. Zero means NO rain at all.

<Furthermore I'm trying to colect information about Relative Humidity and Water Content at 1,7m high. I created a thin layer at approximadetly 1,7m as you can see in the picture below.

There is no need for this layer. Just select the appropriat position in WUFIGraph.

<When I want to get the results if I select the rose element as in picture below Am I doing this right?

If you are interested in that special coordinate - yes.

<I inserted another material in WUFI database but when I try to simulate WUFI gives me this error:

Check the data - you are missing something most likely.

Thanks for your quick reply!

I still can't identify what data is missing in the new material. In this link (http://feupload.fe.up.pt/get/KP39JlfxwiP5pMO) you can see all the information that I introduced in WUFI in order to create a new material.

Thanks for trying to help me.

Could you export the material data (button "export") and post the xml data?

Here you are:

<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="wufimaterial.xslt"?>
<WUFIMaterial UnitSystem="0">
<Material version="2" dbID="0">
<Name>*Pedra de Ançã</Name>
<Info></Info>
<Color>$808080</Color>
<Func6ReadOnlyIndex>1</Func6ReadOnlyIndex>
<IsProduct>FALSE</IsProduct>
<ManufacturerID>-1</ManufacturerID>
<ProductWebLink></ProductWebLink>
<DateDB>1899-12-29 00:00:00</DateDB>
<UpdateDB>1899-12-29 00:00:00</UpdateDB>
<IsLocked>FALSE</IsLocked>
<Scalars Count="13">
<Scalar id="1" name="Bulk density" unit="kg/m³" value="2155,0"/>
<Scalar id="2" name="Porosity" unit="m³/m³" value="0,197"/>
<Scalar id="3" name="Specific Heat Capacity, Dry" unit="J/kgK" value="1000,0"/>
<Scalar id="4" name="Thermal Conductivity, Dry ,10°C" unit="W/mK" value="1,33"/>
<Scalar id="5" name="Water Vapour Diffusion Resistance Factor" unit=" - " value="29,4"/>
<Scalar id="6" name="Reference Water Content" unit="kg/m³" value="1,7"/>
<Scalar id="7" name="Additional Rel. Humidity" unit=" - " value=""/>
<Scalar id="8" name="Additional Water Content" unit="kg/m³" value=""/>
<Scalar id="9" name="Free Water Saturation" unit="kg/m³" value="188,0"/>
<Scalar id="10" name="Water Absorption Coefficient" unit="kg/m²s^0.5" value="0,024"/>
<Scalar id="11" name="Drying Factor" unit=" - " value="10"/>
<Scalar id="12" name="Moisture-dep. Thermal Cond. Supplement" unit="%/M.-%" value=""/>
<Scalar id="13" name="Typical Built-In Moisture" unit="kg/m³" value="1,58"/>
<Scalar id="14" name="Temp-dep. Thermal Cond. Supplement" unit="W/mK²" value=""/>
<Scalar id="15" name="Thermal Conductivity, Design Value" unit="W/mK" value=""/>
</Scalars>
<Functions>
<Function id="1" name="Moisture Storage Function" version="1">
<Generated>FALSE</Generated>
<GenerationMode>0</GenerationMode>
<Items Count="19" version="2" xunit=" - " yunit="kg/m³">
<Item Index="1" x="0,0" y="0,0"/>
<Item Index="2" x="0,04" y="0,52151"/>
<Item Index="3" x="0,112" y="0,5926"/>
<Item Index="4" x="0,348" y="0,8728"/>
<Item Index="5" x="0,586" y="1,043"/>
<Item Index="6" x="0,763" y="1,09697"/>
<Item Index="7" x="0,8" y="1,5835"/>
<Item Index="8" x="0,9" y="2,1169"/>
<Item Index="9" x="0,92" y="2,3186"/>
<Item Index="10" x="0,95" y="2,8"/>
<Item Index="11" x="0,96" y="3,0591"/>
<Item Index="12" x="0,98" y="4,0141"/>
<Item Index="13" x="0,99" y="5,28846"/>
<Item Index="14" x="0,995" y="6,8416"/>
<Item Index="15" x="0,999" y="12,4988"/>
<Item Index="16" x="0,9995" y="16,0858"/>
<Item Index="17" x="0,9999" y="28,1802"/>
<Item Index="18" x="0,99995" y="35,3582"/>
<Item Index="19" x="1,0" y="188,0"/>
</Items>
</Function>
<Function id="2" name="Liquid Transport Coefficient, Suction" version="1">
<Generated>TRUE</Generated>
<GenerationMode>0</GenerationMode>
<Items Count="1" version="2" xunit="kg/m³" yunit="m²/s">
<Item Index="1" x="0" y="0"/>
</Items>
</Function>
<Function id="3" name="Liquid Transport Coefficient, Redistribution" version="1">
<Generated>TRUE</Generated>
<GenerationMode>0</GenerationMode>
<Items Count="1" version="2" xunit="kg/m³" yunit="m²/s">
<Item Index="1" x="0" y="0"/>
</Items>
</Function>
<Function id="4" name="Thermal Conductivity, moisture-dependent" version="1">
<Generated>FALSE</Generated>
<GenerationMode>0</GenerationMode>
<Items Count="1" version="2" xunit="kg/m³" yunit="W/mK">
<Item Index="1" x="0" y="1,33"/>
</Items>
</Function>
<Function id="5" name="Water Vapour Diffusion Resistance Factor, moisture-dependent" version="1">
<Generated>FALSE</Generated>
<GenerationMode>0</GenerationMode>
<Items Count="1" version="2" xunit=" - " yunit=" - ">
<Item Index="1" x="0" y="29,4"/>
</Items>
</Function>
<Function id="6" name="Thermal Conductivity, temperature-dependent" version="1">
<Generated>FALSE</Generated>
<GenerationMode>0</GenerationMode>
<Items Count="1" version="2" xunit="°C" yunit="W/mK">
<Item Index="1" x="10" y="1,33"/>
</Items>
</Function>
<Function id="7" name="Enthalpy, temperature-dependent" version="1">
<Generated>FALSE</Generated>
<GenerationMode>0</GenerationMode>
<Items Count="1" version="2" xunit="°C" yunit="J/kg">
<Item Index="1" x="0,0" y="0,0"/>
</Items>
</Function>
</Functions>
</Material>
</WUFIMaterial>



In your last post you said about raind reduction factor that "Zero means NO rain at all. ". I simulated with rain reduction factor=0 and =1.
With rrf=0 I obtained this:




and with rrf=1 this:




Is this right? If we have all the rain from the climate file in the 2nd picture shouldn't this be more humid in the outter surface (left side)?

<Is this right? If we have all the rain from the climate file in the 2nd picture shouldn't this be more humid in the outter surface (left side)?

Why do you think it should?

veitner wrote:<Is this right? If we have all the rain from the climate file in the 2nd picture shouldn't this be more humid in the outter surface (left side)?

Why do you think it should?

I'm sorry but i've got confused with colours. In fact with rrf=1 we can see in the profile that is more humid (color yellow is higher).

Did you see the .xml data in my last post? I still have the same error when I try to simulate.

Regarding your material:

I guess you are simulating a "suction-experiment". Because of the steep moisture storage function (rh,wc;0.99995,35;1,188) you need to reduce the under relaxation factor of the humidity equation (to about 0.1) and change the factors SOR and NSW to 0.01 and 20 (alternatively use the ADI-Solver). For such experiments it might be interesting to reduce the timestep to watch the forwarding water front in more detail.

Whenever this material is exposed to rain you will probably need to change above factors.

Do you use measured data for the moisture storage function?

veitner wrote:Regarding your material:

I guess you are simulating a "suction-experiment". Because of the steep moisture storage function (rh,wc;0.99995,35;1,188) you need to reduce the under relaxation factor of the humidity equation (to about 0.1) and change the factors SOR and NSW to 0.01 and 20 (alternatively use the ADI-Solver). For such experiments it might be interesting to reduce the timestep to watch the forwarding water front in more detail.

Whenever this material is exposed to rain you will probably need to change above factors.

Do you use measured data for the moisture storage function?

I made the changes that you adviced me to do and so far it's ok. I reduced the time step for half an hour. All the data I'm using is measured data from experimental.

Thanks for your quick reply.

Hello again

Now I'm simulating the stone but with ventilation walls as you can see in the picture below:




but when I press the start button the program gives me this error:




Any ideas about what's wrong? I checked all the material data and climate/surface but I still have this error..............

In addition to the error I posted above, I'm facing the error below when I simulate a wall with 40cm of thickness and 2m high selecting as exterior climate Tromsoe:




Thanks for reading and trying to help me.