A wedge with a mass of 241 kg and an initial velocity of 6.15 m/s is dropped at t=0 into water. The full complete FSI problem is solved and the impact force and wedge velocity can be compared to the experience.
Fluid pressure fringes
*KEYWORD *TITLE *CONTROL_IMPLICIT_DYNAMICS *CONTROL_IMPLICIT_GENERAL *CONTROL_IMPLICIT_SOLUTION *CONTROL_TERMINATION *DATABASE_BINARY_D3PLOT *DEFINE_CURVE_TITLE *DEFINE_FUNCTION *ELEMENT_SHELL *ICFD_BOUNDARY_FREESLIP *ICFD_BOUNDARY_FSI *ICFD_BOUNDARY_NONSLIP *ICFD_CONTROL_ADAPT_SIZE *ICFD_CONTROL_FSI *ICFD_CONTROL_OUTPUT *ICFD_CONTROL_TIME *ICFD_DATABASE_DRAG *ICFD_DATABASE_TIMESTEP *ICFD_MAT *ICFD_PART *ICFD_PART_VOL *ICFD_SECTION *INCLUDE *INITIAL_VELOCITY_RIGID_BODY *LOAD_BODY_Y *MAT_RIGID *MESH_BL *MESH_INTERF *MESH_SURFACE_ELEMENT *MESH_SURFACE_NODE *MESH_VOLUME *NODE *PARAMETER *PART *SECTION_SHELL *END
$-----------------------------------------------------------------------------
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$ Example provided by Iñaki (LSTC)
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$ Web: http://www.dynamore.de
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$ Copyright, 2015 DYNAmore GmbH
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$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
ICFD Free falling Wedge impact
*INCLUDE
mesh.k
*INCLUDE
struc.k
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
$ $
$ PARAMETERS $
$ $
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
*PARAMETER
R T_end 0.03
R dt_plot 5e-4
$
$--- Fluid
$
Rrho_fluid 1000
R mu_fluid 0.001
R dt_fluid 1e-4
R grav 9.81
$
$---+----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
0
*ICFD_CONTROL_OUTPUT
$# msglv
3
$---+----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_VOL
$# pid secid mid
7 1 1
$# spid1 spid2 spid3 spid4
4 5 6
*ICFD_PART_VOL
$# pid secid mid
8 1 2
$# spid1 spid2 spid3 spid4
1 2 3 6
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
$ $
$ ICFD BOUNDARY/INITIAL CONDITIONS $
$ $
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
*ICFD_BOUNDARY_NONSLIP
$# pid
1
*ICFD_BOUNDARY_NONSLIP
$# pid
2
*ICFD_BOUNDARY_FSI
$# pid
1
*ICFD_BOUNDARY_FSI
$# pid
2
*ICFD_BOUNDARY_FREESLIP
$# pid
3
*ICFD_BOUNDARY_FREESLIP
$# pid
4
*ICFD_BOUNDARY_FREESLIP
$# pid
5
*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
10
$# pid1 pid2 pid3 pid4 pid5
1 2 3 4 5
*MESH_INTERF
$# volid
10
$# pid1 pid2 pid3 pid4 pid5
6
*MESH_BL
$# pid nelth
1 1
*MESH_BL
$# pid nelth
2 1
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
$ $
$ DATABASE (OUTPUT) $
$ $
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
*ICFD_DATABASE_DRAG
$# pid
1
*ICFD_DATABASE_DRAG
$# pid
2
*ICFD_DATABASE_TIMESTEP
$# outlv
1
*DATABASE_BINARY_D3PLOT
&dt_plot
*END
A wedge with a mass of 241 kg and an initial velocity of 6.15 m/s is dropped at t=0 into water. The full complete FSI problem is solved and the impact force and wedge velocity can be compared to the experience.
References :
[1] K. M. T. Kleefsman, G. Fekken, A. E. P. Veldman, B. Iwanowski, and
B. Buchner, “A volume-of-fluid based simulation method for wave
impact problems,” J. Comput. Phys., vol. 206, pp. 363–393, June
2005.
[2] R. Zhao and O. Faltinsen, “Water entry of two-dimensional bodies,”
Journal of Fluid Mechanics, vol. 246, pp. 593–612, 1 1993.
[3] S. Wang, “Assessment of slam induced loads on two dimensional
wedges and ship sections,” Master’s thesis, Instituto Superior Tecnico,
Universidade Tecnica de Lisboa, Lisbon,Portugal, 2011.
[4] R. Marcer, C. Berhault, C. de Jouette, N. Moirod, and L. Shen,
“Validation of cfd codes for slamming,” (Lisbon, Portugal), V
European Conference on Computation Fluid Dynamics, June 2010.
[5] X. Mei, Y. Liu, and D. K. Yue, “On the water impact of general
two-dimensional sections,” Applied Ocean Research, vol. 21, no. 1,
pp. 1 – 15, 1999.