Learning Forum

[Sifiso Mngonyama]

Hi Everyone

Can someone kindly explain in detail how I can easily add the term highlighted in the equation below to the general scalar transport equation in fluent since all the other terms are already accounted for?

[SRP]

Hi,

Transport equation consists of unsteady term, convection term, diffusion term, and source term. Can you please explain what the underline term describes?

Thank you

[Sifiso Mngonyama]

Hi

The equation describes the transport of a radioactive gas called thoron an isotope of radon with a half-life of t1/2= 55.6 s. As seen from the equation all the other terms you mentioned are taken care of except for the extra term which accounts for the radioactive decay of the thoron. The λ is the decay constant of the thoron and is defined as λ= ln 2/t1/2= ln 2/(55.6 s) =1.25x10^-2 s^-1. I could probably include that term in the source term but I don't know how to edit the source term in the general transport equation in ansys cause I'm new to ansys. Please help

[Sifiso Mngonyama]

Please help!

[SRP]

Hi,

You can create a UDF using a macro DEFINE_SOURCE.

For more details, I recommend you to refer to Fluent Customization manual: 2.3. Model-Specific DEFINE Macros (ansys.com)

If you are not able to access the link, please refer to this forum discussion: /forum/forums/topic/using-help-with-links/#latest

Thank you

[Sifiso Mngonyama]

Hi,

Thank you very much for your help. I will try that.