This LS-DYNA simulation shows a simple ICFD free convection problem. Since the solver is incompressible, density is a constant. Instead, the tiny density variations due to the rise in temperature are approximated by a external force applied on the system and function of the fluid’s thermal expansion coefficient, gravity and fluid temperature (Boussinesq approximation). Depending on the Raleigh number value, different vortex behaviors can be observed.
This LS-DYNA simulation shows a simple ICFD free convection problem. Since the solver is incompressible, density is a constant. Instead, the tiny density variations due to the rise in temperature are approximated by a external force applied on the system and function of the fluid’s thermal expansion coefficient, gravity and fluid temperature (Boussinesq approximation). Depending on the Raleigh number value, different vortex behaviors can be observed.
Fluid temperature fringes and velocity vectors
*KEYWORD *TITLE *DATABASE_BINARY_D3PLOT *DEFINE_CURVE_TITLE *ICFD_BOUNDARY_PRESCRIBED_TEMP *ICFD_BOUNDARY_NONSLIP *ICFD_CONTROL_TIME *ICFD_DATABASE_TEMP *ICFD_INITIAL *ICFD_MAT *ICFD_PART *ICFD_PART_VOL *ICFD_SECTION *INCLUDE *LOAD_BODY_Y *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 R8.0.0 (or higher) with double precision
$X
$X------------------------------------------------------------------------------
$# UNITS: Dimensionless.
$X------------------------------------------------------------------------------
$X
*KEYWORD
*TITLE
ICFD Natural convection flow
*INCLUDE
mesh.k
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
$ $
$ PARAMETERS $
$ $
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
*PARAMETER
R T_end 30.0
R dt_plot 1.00
$
$--- Fluid
$
Rrho_fluid 37.8
R mu_fluid 1.
R dt_fluid 0.010
RTemp_init 0.000
RTemp_w1 1.000
RTemp_w2 0.000
R HC_fluid 0.7
R TC_fluid 1.
Rthc_fluid 1.
R grav 1.
$ Prandtl number : 0.7
$
$ Raleigh number : ( grav thc_fluid L^3 rho_fluid^2 hc_fluid ) / ( tc_fluid) : 10e3
$---+----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
$---+----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
$# hc tc beta
&HC_fluid &tc_fluid&thc_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_NONSLIP
$# pid
1
*ICFD_BOUNDARY_NONSLIP
$# pid
2
*ICFD_BOUNDARY_NONSLIP
$# pid
3
*ICFD_BOUNDARY_NONSLIP
$# pid
4
*ICFD_BOUNDARY_PRESCRIBED_TEMP
$# pid lcid
1 3
*ICFD_BOUNDARY_PRESCRIBED_TEMP
$# pid lcid
2 4
*ICFD_INITIAL
$# pid vx vy vz temp
0 &Temp_init
*DEFINE_CURVE_TITLE
Temp wall 1
$# lcid sidr sfa sfo offa offo dattyp
3 &Temp_w1
$# a1 o1
0.0 1.0
10000.0 1.0
*DEFINE_CURVE_TITLE
Temp wall 2
$# lcid sidr sfa sfo offa offo dattyp
4
$# a1 o1
0.0 &Temp_w2
10000.0 &Temp_w2
*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
5
$# pid1 pid2 pid3 pid4
1 2 3 4
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
$ $
$ DATABASE (OUTPUT) $
$ $
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
*ICFD_DATABASE_TEMP
$# pid
3
*ICFD_DATABASE_TEMP
$# pid
4
*DATABASE_BINARY_D3PLOT
&dt_plot
*END
