Basics : Mesh Morphing — Welcome to LS-DYNA Examples

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In some cases with imposed Lagrangian displacements, it may be interesting to keep the node topology close to the object of interest. This can save calculation time and may increase accuracy. This can be done by defining two separate volumes and by imposing the displacement on a volume through the use of ICFD_CONTROL_IMPOSED_MOVE. The interface between the two volumes is then defined by MESH_INTERF. This is not compatible with remeshing.

Animated Result

Fluid velocity fringes

plate

 

 

Keywords

*DATABASE_BINARY_D3PLOT
*DEFINE_CURVE_FUNCTION
*DEFINE_CURVE_TITLE
*END
*ICFD_BOUNDARY_FREESLIP
*ICFD_BOUNDARY_PRESCRIBED_VEL
*ICFD_BOUNDARY_PRESCRIBED_PRE
*ICFD_BOUNDARY_NONSLIP
*ICFD_CONTROL_IMPOSED_MOVE
*ICFD_CONTROL_TIME
*ICFD_DATABASE_DRAG
*ICFD_MAT
*ICFD_PART
*ICFD_PART_VOL
*ICFD_SECTION
*INCLUDE
*KEYWORD
*MESH_BL 
*MESH_INTERF
*MESH_SURFACE_ELEMENT
*MESH_SURFACE_NODE
*MESH_VOLUME
*PARAMETER
*TITLE

Reduced Input

$-----------------------------------------------------------------------------
$
$ 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 R9.0.0 (or higher) with double precision 
$X
$X------------------------------------------------------------------------------
$# UNITS: Dimensionless. 
$X------------------------------------------------------------------------------
$X
*KEYWORD
*TITLE
ICFD Cylinder flow - Mesh Morphing
*INCLUDE
mesh.k
*INCLUDE
mesh_interf.k
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
$                                                                              $
$                             PARAMETERS                                       $
$                                                                              $
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
*PARAMETER
R    T_end      40.0
R  dt_plot      0.50
$
$--- Fluid
$
R  v_inlet       1.0
Rrho_fluid       1.0
R mu_fluid     0.005 
R dt_fluid     0.050
$
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
$                                                                              $
$                           ICFD CONTROL CARDS                                 $
$                                                                              $
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
*ICFD_CONTROL_TIME
$#     ttm        dt
    &T_end &dt_fluid
*ICFD_CONTROL_IMPOSED_MOVE
$#     pid    lcidvx    lcidvy    lcidvz
         4                   5
*ICFD_CONTROL_IMPOSED_MOVE
$#     pid    lcidvx    lcidvy    lcidvz
        20                   5
*DEFINE_CURVE_FUNCTION
5
2*3.14/10*sin(2*3.14/10*TIME+3.14/2)
$---+----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
$#     pid     secid       mid 
         5         1         1
*ICFD_PART_VOL
$#     pid     secid       mid 
        10         1         1
$#   spid1     spid2     spid3     spid4
         1         2         3         5
*ICFD_PART_VOL
$#     pid     secid       mid 
        20         1         1
$#   spid1     spid2     
         5         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               
$#                a1                  o1
                 0.0                  0.
                 5.0                  0.
                 6.0            &v_inlet
             10000.0            &v_inlet
*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     
        10
$#    pid1      pid2      pid3      pid4     
         1         2         3         4     
*MESH_BL
$#     pid     nelth
         4         1
*MESH_INTERF
$#   volid     
        10
$#    pid1                
         5  
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
$                                                                              $
$                             DATABASE (OUTPUT)                                $
$                                                                              $
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
*ICFD_DATABASE_DRAG
$#     pid
         4
*DATABASE_BINARY_D3PLOT
&dt_plot
*END
 

Figures

figure_001

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Description

In some cases with imposed Lagrangian displacements, it may be interesting to keep the node topology close to the object of interest. This can save calculation time and may increase accuracy. This can be done by defining two separate volumes and by imposing the displacement on a volume through the use of ICFD_CONTROL_IMPOSED_MOVE. The interface between the two volumes is then defined by MESH_INTERF. This is not compatible with remeshing.