CFD Setup Workflow

Enter the core flow and mesh assumptions once. Abecator carries them through Reynolds number, turbulence inlet variables, y+, first-cell height, boundary-layer scale, prism-layer sizing and a convective Courant time-step check.

One input set8 linked checksRuns locallyNo account required

01 — FLOW STATE

Define the reference flow.

Use conditions representative of the wall or inlet region you are preparing.

Flow type Fluid preset Velocity Um/s Characteristic length LmExternal: streamwise reference length. Internal: use hydraulic diameter for the Re/wall-shear check. Density ρkg/m³ Dynamic viscosity μPa·s

02 — TURBULENCE INLET

Turn inlet assumptions into k, ε and ω.

The workflow uses the standard engineering relations based on turbulence intensity and length scale with Cμ = 0.09.

Turbulence intensity% Length scale / L%A starting assumption only. Use better experimental or upstream-flow information when available.

03 — WALL MESH

Build the near-wall stack.

First-cell height comes from the target y+ and an engineering wall-shear estimate. Prism thickness is then calculated geometrically.

Target y+— Prism layerslayers Prism growth rate× Minimum convective/core cellmUsed for the Courant estimate and prism-to-core transition check; not automatically replaced by the first wall-normal cell.

04 — TRANSIENT SCALE

Set a convective timestep target.

This is a Courant-based starting scale, not a universal transient-stability limit.

Target Courant numberCo

All engineering inputs and calculations stay in your browser. Abecator analytics record only anonymous page/tool interaction events, not your CFD values.

Detailed y+ calculatorChange skin-friction model or supply your own Cf. Detailed turbulence calculatorInspect k, ε and ω independently. Detailed Courant calculatorExplore Δt, Δx and velocity combinations.

WHAT THIS WORKFLOW DOES

It connects setup decisions that are usually made in separate calculators.

The result is not a solver-specific prescription. It is an engineering consistency check: the same velocity, fluid properties and characteristic length propagate into Reynolds number, wall shear, turbulence values, prism sizing and transient scales.

That makes contradictions easier to spot before a large CFD model is built.

Flow regime. Re = ρUL/μ establishes the scale used by the wall-shear check.

Turbulence inlet. k, ε and ω use the supplied intensity and length-scale assumptions.

Near-wall mesh. y = y+ν/uτ provides the first-cell estimate, followed by geometric prism growth.

Transient scale. Δt = Co·Δx/U provides a convective Courant starting point.

WHEN THE SIMPLE CHECK IS NOT ENOUGH

Move from setup arithmetic into CFD diagnosis.

Separated flow, roughness, rotation, strong pressure gradients, multiphase physics and complex wall treatments can invalidate simple correlations.

TECHNICAL CASE

CFD Setup Workflow

Define the reference flow.

Turn inlet assumptions into k, ε and ω.

Build the near-wall stack.

Set a convective timestep target.

It connects setup decisions that are usually made in separate calculators.

Move from setup arithmetic into CFD diagnosis.

y+ misses the target

Prism layers collapse

CFD model review