Intermediate : Sinking Sphere — Welcome to LS-DYNA Examples

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In this FSI example, a solid sphere with a density close to water is allowed to freely sink. Remeshing is triggered and the the finer mesh zone follows the sphere’s displacements.

Animated Result

Fluid velocity fringes

dam

 

Keywords

*KEYWORD
*TITLE
*DATABASE_BINARY_D3PLOT
*DEFINE_CURVE_TITLE
*CONTROL_IMPLICIT_GENERAL
*CONTROL_IMPLICIT_DYNAMICS
*CONTROL_TERMINATION
*ICFD_BOUNDARY_FREESLIP
*ICFD_BOUNDARY_FSI
*ICFD_BOUNDARY_NONSLIP
*ICFD_CONTROL_FSI
*ICFD_CONTROL_OUTPUT
*ICFD_CONTROL_TIME
*ICFD_DEFINE_POINT
*ICFD_MAT
*ICFD_PART
*ICFD_PART_VOL
*ICFD_SECTION
*INCLUDE
*LOAD_BODY_Y
*MAT_RIGID
*MESH_BL
*MESH_INTERF
*MESH_SIZE_SHAPE
*MESH_SURFACE_ELEMENT
*MESH_SURFACE_NODE
*MESH_VOLUME
*NODE
*PARAMETER
*PART
*SECTION
*END

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 Dev 121000 (or higher) with double precision 
$X
$X------------------------------------------------------------------------------
$# UNITS: (kg/m/s) 
$X------------------------------------------------------------------------------
$X
*KEYWORD
*TITLE
ICFD Sphere sinking
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
$                                                                              $
$                             PARAMETERS                                       $
$                                                                              $
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
*PARAMETER
R    T_end       0.2
R  dt_plot      5e-3
$
$--- Fluid
$
Rrho_fluid      1000
R mu_fluid     0.001 
R dt_fluid      5e-4
R  grav         9.81
$
$--- Struc
$
Rrho_struc     2540.
RE_struc        2e11
Rnu_struc        0.3
*INCLUDE
mesh.k
*INCLUDE
struc.k
*DATABASE_BINARY_D3PLOT
&dt_plot
$
$---+----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_FSI
$#     owc        bt
         0  
*ICFD_CONTROL_OUTPUT
$#   msglv
         3
*ICFD_CONTROL_ADAPT_SIZE
$#   asize
         1        20
$---+----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_MAT
$#     mid       flg        ro       vis          
         2         0        
*ICFD_PART
$#     pid     secid       mid 
         1         1         2
*ICFD_PART
$#     pid     secid       mid 
         2         1         2
*ICFD_PART
$#     pid     secid       mid 
         3         1         2
*ICFD_PART
$#     pid     secid       mid 
         4         1         1
*ICFD_PART
$#     pid     secid       mid 
         5         1         1
*ICFD_PART
$#     pid     secid       mid 
         6         1         1
*ICFD_PART
$#     pid     secid       mid 
         7         1         1
*ICFD_PART_VOL
$#     pid     secid       mid 
         8         1         2
$#   spid1     spid2     spid3     spid4     spid5     spid6     spid7     spid8
         1         2         3         4                        
*ICFD_PART_VOL
$#     pid     secid       mid 
        16         1         1
$#   spid1     spid2     spid3     spid4     spid5     spid6     spid7     spid8
         4         5         6         7    
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
$                                                                              $
$                    ICFD BOUNDARY/INITIAL CONDITIONS                          $
$                                                                              $
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
*ICFD_BOUNDARY_FSI
$#     pid   
         1
*ICFD_BOUNDARY_FSI
$#     pid   
         5
*ICFD_BOUNDARY_NONSLIP
$#     pid   
         1
*ICFD_BOUNDARY_NONSLIP
$#     pid   
         5
*ICFD_BOUNDARY_FREESLIP
$#     pid   
         2
*ICFD_BOUNDARY_FREESLIP
$#     pid   
         3
*ICFD_BOUNDARY_FREESLIP
$#     pid   
         6   
*ICFD_BOUNDARY_FREESLIP
$#     pid   
         7
*LOAD_BODY_Y
$#    lcid        sf       
         1         1          
*DEFINE_CURVE_TITLE
Gravity force
$#    lcid      sidr       sfa       sfo      offa      offo    dattyp
         1                    &grav
$#                a1                  o1
                 0.0                 1.0
             10000.0                 1.0
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
$                                                                              $
$                            ICFD MESH KEYWORDS                                $
$                                                                              $
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
*MESH_VOLUME
$#   volid     
        30
$#    pid1      pid2      pid3      pid4      pid5      pid6      pid7      pid8    
         1         2         3         5         6         7        
*MESH_INTERF
$#     pid     
        30
$#   spid1
         4
*MESH_BL
         1         1
*MESH_BL
         5         1
*MESH_SIZE_SHAPE
sphere,1,1
   0.00025      0.01         3
*ICFD_DEFINE_POINT
         1         0         0         0         1
*END

Figures

figure_001

Download

In this FSI example, a solid sphere with a density close to water is allowed to freely sink. Remeshing is triggered and the the finer mesh zone follows the sphere’s displacements. Results can be compared to experiments.

References :

[1] : A Smooth Particle Hydrodynamics discretization for the modelling
of free surface flows and rigid body dynamics. Ricardo B. Canelas. Jose M. Domínguez, Alejandro J.C. Crespo,
Moncho Gómez-Gesteira and Rui M.L. Ferreira

Description

In this FSI example, a solid sphere with a density close to water is allowed to freely sink. Remeshing is triggered and the the finer mesh zone follows the sphere’s displacements. Results can be compared to experiments.

References :

[1] : A Smooth Particle Hydrodynamics discretization for the modelling
of free surface flows and rigid body dynamics. Ricardo B. Canelas. Jose M. Domínguez, Alejandro J.C. Crespo,
Moncho Gómez-Gesteira and Rui M.L. Ferreira