Basics : Potential flow
Despite its limitations (no boundary layer effects, irrotational flow), the solution given by a potential flow solver is very fast and can be used in certain configuration to give a quick approximation of the fluid flow. In this example, after the solve of the potential flow, the pressure is passed to the solid mechanics solver (linear FSI) and the vibrations of the structure can be analysed.
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Basics : Potential flow
Despite its limitations (no boundary layer effects, irrotational flow), the solution given by a potential flow solver is very fast and can be used in certain configuration to give a quick approximation of the fluid flow. In this example, after the solve of the potential flow, the pressure is passed to the solid mechanics solver (linear FSI) and the vibrations of the structure can be analysed.
Fluid pressure fringes
*KEYWORD *TITLE *DATABASE_BINARY_D3PLOT *DEFINE_CURVE_TITLE *ICFD_BOUNDARY_FSI *ICFD_BOUNDARY_NONSLIP *ICFD_DATABASE_DRAG *ICFD_CONTROL_GENERAL *ICFD_CONTROL_FSI *ICFD_MAT *ICFD_PART *ICFD_PART_VOL *ICFD_SECTION *INCLUDE *MESH_SURFACE_ELEMENT *MESH_SURFACE_NODE *MESH_VOLUME *PARAMETER *END
$-----------------------------------------------------------------------------
$
$ Example provided by Iñaki (LSTC)
$
$ E-Mail: info@dynamore.de
$ Web: http://www.dynamore.de
$
$ Copyright, 2015 DYNAmore GmbH
$ Copying for non-commercial usage allowed if
$ copy bears this notice completely.
$
$X------------------------------------------------------------------------------
$X
$X 1. Run file as is.
$X Requires LS-DYNA MPP R10.1 (or higher) with double precision
$X
$X------------------------------------------------------------------------------
$# UNITS: SI.
$X------------------------------------------------------------------------------
$X
*KEYWORD
*TITLE
ICFD Linear FSI with potential Flow
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
$ $
$ PARAMETERS $
$ $
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
*PARAMETER
R T_end 10.0
R dt_plot 0.1
$
$--- Fluid
$
R v_inlet 50.
Rrho_fluid 1.2
R mu_fluid 1.8-5
R dt_fluid 0.000
$
$
$---Struc
$
Rrho_struc 7200.0
R E_struc 20000.0
R nu_struc 0.4
R stiff_y 7000.0
Rstiff_rot 4000.0
R dt_ascii 0.005
*INCLUDE
struc.k
$*END
*INCLUDE
mesh.k
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
$ $
$ ICFD CONTROL CARDS $
$ $
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
*ICFD_CONTROL_GENERAL
1 2
*ICFD_CONTROL_FSI
0
*ICFD_BOUNDARY_FSI
4
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
$ $
$ ICFD PARTS/ SECTION/ MATERIAL $
$ $
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
*ICFD_SECTION
$# sid
1
*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
$# pid secid mid
4 1 1
*ICFD_PART_VOL
$# pid secid mid
10 1 1
$# spid1 spid2 spid3 spid4
1 2 3 4
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
$ $
$ ICFD BOUNDARY/INITIAL CONDITIONS $
$ $
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
*ICFD_BOUNDARY_PRESCRIBED_VEL
$# pid dof vad lcid
1 1 1 1
*ICFD_BOUNDARY_PRESCRIBED_VEL
$# pid dof vad lcid
1 2 1 2
*ICFD_BOUNDARY_PRESCRIBED_PRE
$# pid lcid sf death birth
2 2
*ICFD_BOUNDARY_FREESLIP
$# pid
3
*ICFD_BOUNDARY_NONSLIP
$# pid
4
*DEFINE_CURVE_TITLE
Velocity inlet
$# lcid sidr sfa sfo offa offo dattyp
1 &v_inlet
$# a1 o1
0.0 1.0
10000.0 1.0
*DEFINE_CURVE_TITLE
Pressure outlet
$# lcid sidr sfa sfo offa offo dattyp
2
$# a1 o1
0.0 0.0
10000.0 0.0
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
$ $
$ ICFD MESH KEYWORDS $
$ $
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
*MESH_VOLUME
$# volid
1
$# pid1 pid2 pid3 pid4
1 2 3 4
$*MESH_BL
$$# pid nelth
$ 4 2
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
$ $
$ DATABASE (OUTPUT) $
$ $
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
*ICFD_DATABASE_DRAG
$# pid
4 1
*DATABASE_BINARY_D3PLOT
&dt_plot
*END
Despite its limitations (no boundary layer effects, irrotational flow), the solution given by a potential flow solver is very fast and can be used in certain configuration to give a quick approximation of the fluid flow. In this example, after the solve of the potential flow, the pressure is passed to the solid mechanics solver (linear FSI) and the vibrations of the structure can be analysed. The drag of the segment set is also output and can be used in a subsequent solid only analysis.