Learning Forum

[nabaglo]

I have a problem with working out the ICFD LS-Dyna model. I downloaded it from https://www.dynaexamples.com/icfd/advanced-examples/copy_of_windkessel.
The i.k file contains the flow input data:
*DEFINE_CURVE
1,,,1,-0.0243,
0,12239
0.0243,126656.2705
0.0328,129456.0407
0.0412,133189.0676
0.0496,137322.0617
0.058,141321.7334
0.0665,146654.629
0.0749,150654.3007
0.0833,153320.7485
0.0917,155987.1963
0.1,157320.4202
0.109,158653.6441
0.117,159986.868
0.125,159986.868
0.134,159986.868
0.142,159986.868
0.151,159986.868
0.159,158653.6441
0.168,155987.1963
0.176,153320.7485
0.184,150654.3007
0.193,147987.8529
0.201,145321.4051
0.21,143988.1812
0.218,141321.7334
0.227,138655.2856
0.235,135988.8378
0.243,134655.6139
0.252,134655.6139
0.26,135988.8378
0.269,138655.2856
0.277,139988.5095
0.286,142654.9573
0.294,143988.1812
0.302,143988.1812
0.311,142654.9573
0.319,141321.7334
0.328,138655.2856
0.336,137322.0617
0.344,135988.8378
0.353,134655.6139
0.361,133322.39
0.37,133055.7452
0.378,132922.4228
0.387,132655.7781
0.395,131589.1989
0.403,130122.6526
0.412,129189.3959
0.42,128656.1064
0.429,128389.4616
0.437,127989.4944
0.446,127589.5272
0.454,127189.5601
0.462,126789.5929
0.471,125989.6586
0.479,125189.7242
0.488,124389.7899
0.496,123589.8555
0.505,123189.8884
*DEFINE_CURVE
My problem: Is the curve enclosing flow velocity or pressure. The liquid in the model is blood then according to the correct blood pressure in arteries 120 mm Hg = 15998.69 Pa. If the curve is enclosing pressure in Pa, the maximum value of the pressure 159986.868 is 10 times bigger than expected 15998.69. Why? Or maybe it is flow velocity but it should be expressed in um/s (micrometers per second)?

 

 

 

 

[Reno Genest]

Hello,

If you open the i.k file in a text editor, you will see at the top of the file that the units are g/cm/s and so pressure is not in Pa; it is in dyne/cm2. Does this make more sense?

https://www.dynasupport.com/howtos/general/consistent-units

Also, note that it is possible that these examples  use fictional material properties and loads. It is up to the user to user proper materials, loading, consistent units, etc.

https://www.dynasupport.com/howtos/general/consistent-units

Let me know how it goes.

 

Reno.