The 2D laminar backward facing step is a widely encountered benchmark for CFD code testing. The present example features a mesh size of 0.05 and a Reynolds number of 800. The second order steady state solver is used, requires LS-DYNA MPP Dev 114223 (or higher) with double precision.
Fluid velocity fringes
*KEYWORD *TITLE *DATABASE_BINARY_D3PLOT *DEFINE_CURVE_TITLE *ICFD_BOUNDARY_NONSLIP *ICFD_BOUNDARY_PRESCRIBED_VEL *ICFD_BOUNDARY_PRESCRIBED_PRE *ICFD_CONTROL_GENERAL *ICFD_CONTROL_OUTPUT *ICFD_CONTROL_STEADY *ICFD_MAT *ICFD_PART *ICFD_PART_VOL *ICFD_SECTION *INCLUDE *MESH_SURFACE_ELEMENT *MESH_SURFACE_NODE *MESH_VOLUME *PARAMETER *END
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$ Example provided by Iñaki (LSTC)
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$X------------------------------------------------------------------------------
$X
$X 1. Run file as is.
$X Requires LS-DYNA MPP Dev 114223 (or higher) with double precision
$X
$X------------------------------------------------------------------------------
$# UNITS: Dimensionless
$X------------------------------------------------------------------------------
$X
*KEYWORD
*TITLE
ICFD Laminar Backward facing step
*INCLUDE
mesh.k
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
$ $
$ PARAMETERS $
$ $
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
*PARAMETER
I It_max 10000
R dt_plot 200
$
$--- Fluid
$
Rrho_fluid 1
R mu_fluid 1.6665e-3
Rvel_fluid 1
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
$ $
$ ICFD CONTROL CARDS $
$ $
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
*ICFD_CONTROL_GENERAL
1 0 0
*ICFD_CONTROL_STEADY
&It_max 1e-8 1e-8 1 1 1 0
*ICFD_CONTROL_OUTPUT
$# msgl
3
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
$ $
$ ICFD PARTS/ SECTION/ MATERIAL $
$ $
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
*ICFD_MAT
$# mid flg ro vis
1 1&rho_fluid &mu_fluid
*ICFD_PART
$# pid secid mid
1 1 1
*ICFD_PART
$# pid secid mid
2 1 1
*ICFD_PART
$# pid secid mid
3 1 1
*ICFD_PART_VOL
$# pid secid mid
10 1 1
$# spid1 spid2 spid3
1 2 3
*ICFD_SECTION
$# sid
1
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
$ $
$ ICFD BOUNDARY/INITIAL/LOAD CONDITIONS $
$ $
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
*ICFD_BOUNDARY_NONSLIP
$# pid
3
*ICFD_BOUNDARY_PRESCRIBED_VEL
$# pid dof vad lcid sf vid death birth
1 1 1 1 1.000000 01.0000E+28 0.000
*ICFD_BOUNDARY_PRESCRIBED_VEL
$# pid dof vad lcid sf vid death birth
1 2 1 2 1.000000 01.0000E+28 0.000
*ICFD_BOUNDARY_PRESCRIBED_PRE
$# pid dof vad lcid sf vid death birth
2 1 1 2 1.000000 01.0000E+28 0.000
*DEFINE_CURVE_TITLE
Vel Inlet
$# lcid sidr sfa sfo offa offo dattyp
1 &vel_fluid
$# a1 o1
0.0 1.0
10000.0 1.0
*DEFINE_CURVE
$# lcid sidr sfa sfo offa offo dattyp
2
$# a1 o1
0.0 0.0
10000.0 0.0
*ICFD_INITIAL
$# pid
0 1
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
$ $
$ ICFD MESH KEYWORDS $
$ $
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
*MESH_VOLUME
$# volid
10
$# pid1 pid2 pid3
1 2 3
*MESH_BL
$# pid
3 1
*MESH_BL_SYM
$# pid
1
*MESH_BL_SYM
$# pid
2
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
$ $
$ DATABASE (OUTPUT) $
$ $
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
*DATABASE_BINARY_D3PLOT
&dt_plot
*END
The 2D laminar backward facing step is a widely encountered benchmark for CFD code testing. The present example features a mesh size of 0.05 and a Reynolds number of 800. The second order steady state solver is used.
References :
[1] B. F. ARMALY, F. DURSTS, J. C. F. PEREIRA AND B. SCHONUNG , Experimental and theoretical investigation of
backward-facing step flow, Institute of Hydromechanics, Section I11 : Mechanics of Turbulent Flows, University of
Karlsruhe, KaiserstraBe 12, D-7500 Karlsruhe, F.R.G.
[2] EXPERIMENTAL AND NUMERICAL INVESTIGATION
OF 2-D BACKWARD-FACING STEP FLOW. T. LEE AND D. MATEESCU
Department of Mechanical Engineering, McGill University, Montreal, Quebec, Canada
[3] E. Erturk,Numerical solutions of 2-D steady incompressible flow over
a backward-facing step, Part I: High Reynolds number solutions,Gebze Institute of Technology, Energy Systems Engineering Department, Gebze, Kocaeli 41400, Turkey