Sudden drop in UDS value
I simulate the moisture loss of a pile of potatoes through which humid air flows. I simulate the situation via a transient 2D model with porous zone. In the solid part of the porous zone I defined a UDS (=moisture content of the potatoes in kg water/kg potato) in the solid part (=the potatoes) of the porous zone (=the pile of potatoes).
I defined a source term for the UDS (=moisture lost via evaporation) in the form of a UDF. In this UDF the source term is related to the temperature and h2o mass fraction in the fluid part (=humid air) of the porous zone. Th humid air is modeled via species transport.
I patch the UDS value in the solid part (0.8), the h2o mass fraction in the fluid part (=0.01065) and the temperature of the solid (288.15K) and fluid (286.15K) part of the porous zone.
When I do some hand calculations the value for the source term is realistic: per m³ potatoes 0.14g of water is lost per second. However, when I run the simulation the UDS value drops immediately to 0 after only 1e-4s.
Can anyone help me with this?
Thanks in advance for your time!