Hey everyone, hoping someone with Fluent/CFD experience can give me some advice. I’m an engineering student modelling flow from a 10 m diameter tank into a 0.25 m pipe through different inlet geometries to determine inlet loss coefficient \(K\). For one bellmouth-style filleted inlet, I’m using: Standard \(k-\varepsilon\) Scalable wall functions Locally scaled residuals to \(10^{-6}\) Second-order discretisation Tet mesh converted to polyhedral due to strict element limits My professor wants us to follow this general workflow quite closely. The issue is the predicted \(K\). Without extra turbulence controls: $$ K \approx 0.44 $$ With Curvature Correction: $$ K \approx 0.35 $$ The reference standard gives about \(K=0.06\), although it is old and gives basically no detail on bellmouth radius, geometry or material. I calculate \(K\) from the pressure difference between a tank reference plane and a downstream plane in a 40D pipe, then subtract straight-pipe friction losses using an independently determined Darcy friction factor. I’m confident this is the intended method. My questions: Would you use Fluent’s Production Limiter for this kind of strongly accelerating/curved inlet flow? When I enable Production Limiter, convergence becomes difficult, especially once I switch to second-order. Has anyone dealt with this? Does anything in the attached mesh look poorly optimised? Mesh quality metrics are healthy, but I’m still learning what actually matters visually. What sensitivity tests would you run before trusting the predicted \(K\)? The inlet/pipe are cement-lined with roughness \(3.5\times10^{-5}\) m. I’m not trying to force the CFD to equal 0.06. I mainly want to understand why the losses are so high and what modelling choices are worth testing. Any advice would be appreciated. https://cdn.discordapp.com/attachments/400697259819270145/1548908083659538632/case3_mesh_inlet.png?ex=6aa8c490&is=6aa77310&hm=f28bcb5fc54ea1638d208c783ced2df7e4ef656459e831d5c2bfd28cfcfda753& https://cdn.discordapp.com/attachments/400697259819270145/1548908084066394112/case_3_mesh_full_tank.png?ex=6aa8c490&is=6aa77310&hm=c49497cf7f17bed9d9a0a49856b04228db21ec53fce2a7cc5a5e7d70b03ca49f&