Backward facing step

Overview

• Solver: simpleFoam
• Experimental case described by Driver and Seegmiller 14
• CFD case based on https://turbmodels.larc.nasa.gov/backstep_val.html
• Reynolds number based on the step height of $Re_h$ 36000
• Reattachment at 6.26+-0.1 x/h
• backwardFacingStep2D

Mesh

• 2D structured mesh created using blockMesh

Boundary conditions

• $U$ 44.2 m/s
• $h$ 1.27 cm

Common fields

Velocity: U

Patch	Condition	Value
Inlet	fixedValue	44.2 m/s in x
Outlet	zeroGradient
Walls	noSlip

Pressure: p

Patch	Condition	Value
Inlet	zeroGradient
Outlet	fixedValue	0 Pa (static)
Walls	zeroGradient

Turbulence fields

• turbulence model: kOmegaSST

Turbulence viscosity: nut

Patch	Condition	Value
Inlet	calculated
Outlet	calculated
Walls	nutUSpaldingWallFunction

kOmega SST

Turbulence kinetic energy: k

Patch	Condition	Value
Inlet	fixedValue	based on 0.061% intensity
Outlet	zeroGradient
Walls	kqRWallFunction

Turbulence specific dissipation rate: omega

Patch	Condition	Value
Inlet	fixedValue	based on nut/nu = 0.009
Outlet	zeroGradient
Walls	omegaWallFunction

Results

Predictions are compared against the measurements by Driver and Seegmiller 14 below