A new more flexible diffusion function to estimate diffusion in a partially air filled pore space is implemented.
The new function is built on the previous have a tortuosity which define the slope in relation to what should be expected for air without any mixture of soil particles.
3 New parameter were introduced D CO2 Min Value Soil, D CO2 PowerCoef and D CO2 Air Threshold.
The first represent the minimum value that is suggested to be close to diffusion in water for CO2. The default value is 1.E-9 m2/s
The PowerCoef is a power coefficient for the air filled fraction of the soil
and the Theshold represent the minimum air content to increase the diffusion above the minimum level.
The a new viewing function is also added (require a update and replacement of the Function.csv file)
In the function above demostrates the view function by changing values and comparing with default settings