Fluids

Fluids

What is Phi_f in UDS_Flux for getting complete advection term?

    • schwaral
      Subscriber
      Hi, nIn the example for defining a UDS_Flux there is this note in the code: n* ANSYS FLUENT will multiply the returned value by phi_f (the scalar'sn value at the face) to get the complete'' advective term. */nWhat is phi_f? nWhy I ask this: nI used the code of the example and compared the results to the mass flow rate option for flux function. I noticed some differences and try to understand where these come from.nnFirst I thought the differences come from the difusive part but when I set the Diffusivity under materials =0, I still notice the difference. n
    • Konstantine Kourbatski
      Ansys Employee
      this is covered in the same manual section 2.7.3. DEFINE_UDS_FLUX, close to the beginning above the examples. See eq. (2-28), phi in that term is what been multiplied by.n
    • Konstantine Kourbatski
      Ansys Employee
      phi is effectively your scalarn
    • schwaral
      Subscriber
      okay but still should not be the results the same if I use default mass flow rate for flux and the example? My solution defnetly converged well with both options and I use the same mesh in a simple 1D case. n
    • schwaral
      Subscriber
      I did further investigations and found out, that i receive same results when the velocity is greater than 0. for a velocity = 0 the default mass-flow-rate and the UDS_Flux Example show different solutions. nLater in my SImulation I have a velocity signal that goes severeal times back to 0 so I really need to find out why this difference appears.n
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