Advanced : Heart Valve

Fluid velocity isosurfaces

*ICFD_BOUNDARY_FSI
*ICFD_BOUNDARY_NONSLIP
*ICFD_BOUNDARY_PRESCRIBED_PRE
*ICFD_CONTROL_ADAPT_SIZE
*ICFD_CONTROL_EMBEDSHELL
*ICFD_CONTROL_FSI
*ICFD_CONTROL_MESH
*ICFD_CONTROL_OUTPUT
*ICFD_CONTROL_TIME
*ICFD_DATABASE_FLUX
*ICFD_DATABASE_FLUX
*ICFD_DATABASE_DRAG
*ICFD_MAT
*ICFD_PART
*ICFD_PART_VOL      
*ICFD_SECTION
*MESH_EMBEDSHELL     
*MESH_VOLUME        

*KEYWORD MEMORY=100000000
*INCLUDE
mesh_cfd.k
*DEFINE_CURVE_TITLE
Inlet Pressure
$#    lcid      sidr       sfa       sfo      offa      offo    dattyp     lcint
         1         0       1.0       1.0       0.0       0.0         0         0
$#                a1                  o1  
                 0.0                 0.0
            0.006278         1333.432983
            0.025112         6666.598145
            0.054933         9999.613281
            0.103587        13332.910156
              0.1287        13332.910156
            0.152242        13332.910156
            0.169507        13332.910156
          0.18834101         8888.797852
            0.202466        -8888.513672
          0.21031401       -27935.710938
            0.238565       -73649.023438
          0.26053801      -100314.898438
          0.26681599           -109838.5
          0.31390101           -109838.5
          0.35470799      -102219.601563
          0.40493301       -96505.609375
          0.49910301       -97775.351563
          0.56143498       -97775.351563
          0.65560502       -97775.351563
            0.759193        -93965.96875
          0.80000001        -78410.71875
          0.85000002                 0.0
*DEFINE_CURVE_TITLE
Outlet Pressure
$#    lcid      sidr       sfa       sfo      offa      offo    dattyp     lcint
         2         0       1.0       1.0       0.0       0.0         0         0
$#                a1                  o1  
                 0.0                 0.0
          0.85000002                 0.0
*ICFD_CONTROL_TIME
$#     ttm        dt       cfl    lcidsf     dtmin     dtmax     
    &end_t   &dt_cfd       1.0         0      1e-5      1e-3
*ICFD_CONTROL_EMBEDSHELL
,,1
*ICFD_CONTROL_OUTPUT
4
*ICFD_CONTROL_MESH
1.6
*ICFD_CONTROL_ADAPT_SIZE
1,100
*ICFD_BOUNDARY_NONSLIP
$#     pid   
         1
*ICFD_BOUNDARY_NONSLIP
$#     pid   
         2
*ICFD_BOUNDARY_NONSLIP
$#     pid   
         3
*ICFD_BOUNDARY_PRESCRIBED_PRE
$#     pid      lcid        sf     death     birth     
         4         1       0.51.00000E28       0.0
*ICFD_BOUNDARY_PRESCRIBED_PRE
$#     pid      lcid        sf     death     birth     
         5         2       1.01.00000E28       0.0
*ICFD_BOUNDARY_NONSLIP
$#     pid   
         6
*ICFD_BOUNDARY_NONSLIP
$#     pid   
         7
*ICFD_MAT
$#     mid       flg        ro       vis        st       thd   
         1         1     1.059     0.035       0.0       
$----------------------------------------------
*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
$#     pid     secid       mid   
         5         1         1
*ICFD_PART
$#     pid     secid       mid   
         6         1         1
*ICFD_PART
$#     pid     secid       mid   
         7         1         1
*ICFD_BOUNDARY_FSI
$#     pid   
         3
*ICFD_CONTROL_FSI
$0,0.001,,,,,10
0
*ICFD_DATABASE_FLUX
$#     pid   
         4
*ICFD_DATABASE_FLUX
$#     pid   
         5
*ICFD_DATABASE_DRAG
$#     pid   
         3
*ICFD_PART_VOL
$#     pid     secid       mid   
        20         1         1
$#   spid1     spid2     spid3     spid4     spid5     spid6     spid7     
         1         2         3         4         5         6         7        
*ICFD_SECTION
$#     sid   
         1
*MESH_EMBEDSHELL
$#   volid     
        20
$#    pid1     
         3      
*MESH_VOLUME
$#   volid     
        20
$#    pid1      pid2      pid3      pid4      pid5      pid6      
         1         2         4         5         6         7        
*END

 ICFD_example_heartvalve.zip

Thanks to its advanced and integrated fluid structure interaction capabilities, LS-DYNA's ICFD solver is capable of successfully solving highly non linear FSI problems such as artificial heart valves and addressing its numerous challenges :

- Strong pressure gradients : special stabilization techniques are developed in order to restrict spurious backflow which can occur in Pressure-Pressure boundary conditions.

- Similar solid and fluid material densities : strong FSI coupling is required. This requires solving the solid mechanics domain using an implicit solver and couple with the ICFD solver in a non linear iterative loop. See *CONTROL_IMPLICIT keywords and *ICFD_CONTROL_FSI/*ICFD_BOUNDARY_FSI

-Thin leaflets that undergo strong deformations : the solid mechanics LS-DYNA solver features advanced contact capabilities (See *CONTACT_..._MORTAR) which allows it to handle strong deformations and contact between thin structures.

 - Extensive mesh deformation and frequent remeshing : One of the strengths of the ICFD solver is its capability of retaining a good quality solution even in highly distorted meshes or during remeshing. See ICFD_CONTROL_ADAPT_SIZE.

- Gap leakage treatment :  See ICFD_CONTROL_EMBEDSHELL, the ICFD solver recently introduced the capability to shut off the flow leakage at non watertight embedded shell intersection points. This new approach effectively prevents any flow escapement once the leaflets have been forced shut.