Learning Forum

[Maheswari Gutta]

Greetings, 

As inlet boundary conditions, I used point profiles - loaded .prof file, and then selected inverse distance interpolation method of the points. But after interpolation, the magnitudes are changed. Inlet profile has 300 points and mesh has 4000 nodes. Is it the problem with my uploaded profile or is this error generally expected?

Thank you 

 

[Rob]

Couple of possibilites. What did you set in Fluent, and what did you report? Then there's the Fluent time step and convergence: I can see faceting on the Fluent data curve. 

[Maheswari Gutta]

Greetings, 

Thank you for the reply. The point profiles are velocities (vx, vy, vz) at (x,y,z). Boundary condition of inlet = velocity (velocity specification method = components). The report is volumetric flow rate at the inlet. The point profiles are generated (and read/applied) at every 0.001 timestep, same as fluent timestep. The convergence criteria are set to 10e-4. 

Are the interpolation values calculated at the nodes or cells or facets? I thought they should be at the nodes.

Thank you

 

[Rob]

Facets in Fluent: data is stored in cell centre for the volumes and on the facet for defined surfaces. Depending on how you recorded the data (ie boundary surface) you may also see some influence from the neighbouring cell value. The value USED in Fluent is as defined, the report may see some influence. 

[Maheswari Gutta]

Greetings,

Thank you for the clarification. Could you share the possible ways to report the 'actual value USED' in Fluent with no influence from neighboring cells?

Thank you

[Rob]

Write a profile out of Fluent if it's steady. If it's transient you're setting the facet values with time. I think facet average may work, but check the surface report definitions.