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An initially loaded spring is released at t=0. A compression wave is formed in the fluid that bounces back and interacts with the structure thus creating an oscillatory system. In this example, the moving mesh technique is used for FSI rather than the classic embedded approach.

Description

An initially loaded spring is released at t=0. A compression wave is formed in the fluid that bounces back and interacts with the structure thus creating an oscillatory system. In this example, the moving mesh technique is used for FSI rather than the classic embedded approach.

Animated Result

CESE Velocity fringes

ezgif.comvideotogif.gif

Keywords

*BOUNDARY_SPC_SET
*CESE_BOUNDARY_FSI_SET
*CESE_BOUNDARY_REFLECTIVE_SET
*CESE_BOUNDARY_SLIDING_SET
*CESE_CONTROL_LIMITER
*CESE_CONTROL_MESH_MOV
*CESE_CONTROL_SOLVER
*CESE_CONTROL_TIMESTEP
*CESE_EOS_IDEAL_GAS
*CESE_INITIAL
*CESE_PART
*CONTROL_TERMINATION
*DATABASE_BINARY_D3PLOT
*DEFINE_CURVE
*ELEMENT_BEAM
*ELEMENT_SHELL
*KEYWORD
*MAT_ELASTIC
*MAT_LINEAR_ELASTIC_DISCRETE_BEAM
*MAT_RIGID
*NODE
*PARAMETER
*PART
*TITLE
*SECTION_BEAM
*SECTION_SHELL
*SET_NODE_LIST_TITLE
*SET_SEGMENT

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 R8.0.0 (or higher) with double precision 
$X
$X------------------------------------------------------------------------------
$# UNITS: (kg/m/s)
$X------------------------------------------------------------------------------
$X
*KEYWORD
*TITLE
CESE Moving mesh Piston example
*INCLUDE
mesh.k
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
$                                                                              $
$                           CESE CONTROL CARDS                                 $
$                                                                              $
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
$
*CESE_CONTROL_SOLVER
$   iframe     iflow     igeom
       100         1         2
*CESE_CONTROL_TIMESTEP
$     iddt       cfl     dtint
         2&cfl_fluid &dt_fluid              
*CESE_CONTROL_LIMITER
$    idlmt      alfa      beta      epsr
         1       1.0       1.0       0.5
*CESE_CONTROL_MESH_MOV
$     ialg   numiter    reltol    abstol
         9       500    1.0e-5    1.0e-5
$  
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
$                                                                              $
$                       CESE PARTS/ EOS/ MATERIAL                              $
$                                                                              $
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8 
*CESE_PART
$      pid       mid     eosid
        12                   3
*CESE_EOS_IDEAL_GAS
$    eosid        cv        cp
         3       &Cv       &Cp
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
$                                                                              $
$                    CESE BOUNDARY/INITIAL CONDITIONS                          $
$                                                                              $
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
*CESE_BOUNDARY_SLIDING_SET
$     ssid
         3
*CESE_BOUNDARY_SLIDING_SET
$     ssid
         4
*CESE_BOUNDARY_FSI_SET
$     ssid
         1
$
*CESE_BOUNDARY_REFLECTIVE_SET
$     ssid
         2
$
*CESE_INITIAL
$      uic       vic       wic     rhoic       pic       tic       hic
       0.0       0.0       0.0     &ro_1      &P_1    
*END

Figures

Cylinder Flow

Download

CESE_example_piston.zip