Basics : Rayleigh-Taylor
This example shows how to set up a simulation of two-phase flow with surface tension. Rayleigh-Taylor instability occurs when a fluid is on top of a lighter one.
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Basics : Rayleigh-Taylor
This example shows how to set up a simulation of two-phase flow with surface tension. Rayleigh-Taylor instability occurs when a fluid is on top of a lighter one.
*TITLE *KEYWORD *DATABASE_BINARY_D3PLOT *DEFINE_CURVE_TITLE *ICFD_BOUNDARY_FREESLIP
*ICFD_BOUNDARY_NONSLIP *ICFD_CONTROL_TIME *ICFD_MAT *ICFD_PART *ICFD_PART_VOL *ICFD_SECTION *INCLUDE *LOAD_BODY_Y *MESH_INTERF *MESH_SURFACE_ELEMENT *MESH_SURFACE_NODE *MESH_VOLUME *PARAMETER *END
$X------------------------------------------------------------------------------
$# UNITS: SI.
$X------------------------------------------------------------------------------
$X
*KEYWORD
*TITLE
$# title
ICFD Rayleigh-Taylor instability
*INCLUDE
mesh.k
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
$ $
$ PARAMETERS $
$ $
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
*PARAMETER
$# prmr1 val1
R T_end 4.0
R dt_plot 0.1
R dt_fluid 1e-2
R ro_h 1.2
R ro_l 0.17
R mu_h 0.003
R mu_l 0.003
R grav 1.0
R st 0.015
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
$ $
$ ICFD PARTS/ SECTION/ MATERIAL $
$ $
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
*ICFD_MAT
$# mid flg ro vis st
1 1 &ro_l &mu_l &st
*ICFD_MAT
$# mid flg ro vis
2 1 &ro_h &mu_h &st
*ICFD_SECTION
$# sid
1
*ICFD_PART_TITLE
$# pid secid mid
upper horizontal boundary
1 1 2
*ICFD_PART_TITLE
$# pid secid mid
upper left vertical boundary
2 1 2
*ICFD_PART_TITLE
$# pid secid mid
upper right vertical boundary
3 1 2
*ICFD_PART_TITLE
$# pid secid mid
lower horizontal boundary
4 1 1
*ICFD_PART_TITLE
$# pid secid mid
lower left vertical boundary
5 1 1
*ICFD_PART_TITLE
$# pid secid mid
lower right vertical boundary
6 1 1
*ICFD_PART_TITLE
$# pid secid mid
initial interface position
7 1 1
*ICFD_PART_VOL
$# pid secid mid
8 1 1
$# spid1 spid2 spid3
4 5 6 7
*ICFD_PART_VOL
$# pid secid mid
9 1 2
$# spid1
1 2 3 7
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
$ $
$ ICFD BOUNDARY/INITIAL CONDITIONS $
$ $
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
*ICFD_BOUNDARY_FREESLIP
$# pid
2
3
5
6
*ICFD_BOUNDARY_NONSLIP
$# pid
1
4
*LOAD_BODY_Y
$# lcid sf
1 1
*DEFINE_CURVE_TITLE
Gravity force
$# lcid sidr sfa
1 &grav
$# a1 o1
0.0 &grav
10000.0 &grav
$
$---+----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 MESH KEYWORDS $
$ $
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
*MESH_VOLUME
$# volid
1
$# spid1 spid2
1 2 3 4 5 6
*MESH_INTERF
$# volid
1
$# spid1
7
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
$ $
$ DATABASE (OUTPUT) $
$ $
$---+----1----+----2----+----3----+----4----+----5----+----6----+----7----+----8
*DATABASE_BINARY_D3PLOT
$# dt
&dt_plot
*END
This example shows how to set up a simulation of two-phase flow with surface tension. Rayleigh-Taylor instability occurs when a fluid is on top of a lighter one. Surface tension tends to stabilize the flow. Results compare well to those available from the literature [1].
[1] Parolini N. Computational fluid dynamics for naval engineering problems. Ph.D. Thesis No. 3138, EPFL, 2004.