OpenFOAM in Practice

[OpenFOAM Tutorial] Backward Facing Step Flow Analysis — Capturing Recirculation Zones with simpleFoam

Scale 0.1 makes the step 0.1 m, while the viscosity note builds Re 1000 with H = 0.01 m. A 6–8H bubble then has two physical lengths.

2026.03.26

[CFD Q&A] When simpleFoam Pressure Residual Fails to Converge

In simpleFoam the pressure residual jumped from 0.412 to 0.891. Dropping the p relaxation from 0.7 to 0.3 brought it near 1e-4 by iteration 200.

2026.03.27

Dean Flow: Analytical Solution and CFD Validation for Helical Pipe Flow

At Re_d = 10000 and a coil radius of 2.3 m the Dean number is about 510, well outside the small-De perturbation used for the stream function.

2026.03.28

Solving an Impeller by Holding It Still — Rotating Frames and MRF

Coriolis and centrifugal sources at 1.2 rad/s, plus the MRF interface map from relative to absolute velocity, checked by a free particle.

2026.06.12

When Gradients Go Wrong on Skewed Meshes — Green–Gauss vs. Weighted Least-Squares Reconstruction

On a flat cell, Green–Gauss can swing the gradient nearly sideways. Distance-weighted least squares cuts the curved-field error from 0.0293 to 0.0222.

2026.07.17

Same Answer From 18% of the Cells — AMR Tagging Criteria and Coarse-Fine Refluxing

Wrapping a 256^2 shear layer in 3-level AMR leaves 11,776 cells, 18% of 65,536. Reflux off drifts mass by about 1% in 60 steps.

2026.08.10