Example h7: Simulation of aortic pressure in a simplified mesenteric artery network

In this example we simulate the aortic pressure cycle (Fig. 1) at the proximal end of the descending aorta in a simplified mesenteric artery network. The tree was created by Peng Du of BME by digitising the visible human data as explained in example_h4. The pressure at the distal ends of the tree is maintained constant at 9 kPa (7.2 mmHg) to maintain continuous blood flow within the network. For details of the governing flow equations and numerical methods etc. see example_h2 and example_h3 .

Fig. 1. Aortic Pressure variation

Fig. 2. Pressure Distribution at 1.09 s (Peak ejection) Fig. 3. Velocity Distribution at 1.09 s (Peak ejection)

The comfile run by this example is as follows:

# Author: Thusitha Mabotuwana
# Last modified: 15.06.06
# com file used to simulate blood flow in the mesenteric artery network.

fem def para;r;bifur;example
fem def coor;r;bifur;example
fem def base;r;bifur;example

fem def node;r;nodeFile;example
fem def elem;r;elementFile;example

fem def field;r;radiiValFile;example
fem def elem;r;radiiEleFile;example field

fem def grid;r;test;example coronary
fem update grid geometry;

fem def equat;r;bifur;example                         
fem defi mate;r;test;example
fem update material field material 4 no_field 1;

fem def time;r;periodic;example
fem def init;r;bifur;example
fem def solv;r;bifur;example

$time_step = 0.00007;

$write_out_period= 0.087; 
# In order to generate Fig2 (at 1.09s), might have to make this much smaller than 0.087. 
# Also, if we want to reconstruct the pressure pulse which has a period of approx. 0.87s using our exnode value (only the 1st value however, ie. value at Node1), 
# we need to make this value sufficiently small so that we have enough values to capture all the characteristics of Fig1.

fem export points;$time_initial grid as vessel offset 0;         
fem export grid;vessel as vessel offset_node 0 elastic_tube; 

for ($time=$time_initial;$time<$time_final;$time=$time+$write_out_period)       
   fem solve restart to $write_out_period delta_t $time_step;        
   fem export points;$time grid as vessel offset 0           

Files used by this example are:

Name                 Modified     Size

example_h7.com 20-Jun-2006 1.5k bifur.ipbase 13-Jun-2006 2.0k bifur.ipcoor 13-Jun-2006 572 bifur.ipequa 13-Jun-2006 1.3k bifur.ipinit 13-Jun-2006 674 bifur.ippara 13-Jun-2006 5.9k bifur.ipsolv 13-Jun-2006 761 elementFile.ipelem 13-Jun-2006 62k nodeFile.ipnode 13-Jun-2006 77k periodic.iptime 13-Jun-2006 2.1k radiiEleFile.ipelfd 13-Jun-2006 23k radiiValFile.ipfiel 13-Jun-2006 15k test.ipgrid 13-Jun-2006 216 test.ipmate 13-Jun-2006 6.7k view.com 13-Jun-2006 1.2k

Download the entire example:

Name                  Modified     Size

examples_h_h7.tar.gz 19-Aug-2006 573k

Testing status by version:

StatusTestedReal time (s)
cmSuccessSun Mar 6 00:23:16 201646
cm-debugSuccessSat Mar 5 01:45:02 2016166
cmSuccessThu Aug 16 05:00:48 2007439
cm-debugSuccessWed Jul 25 05:11:28 20072023
cm-debug-clear-mallocSuccessSat Aug 18 05:12:41 20072034
cm-debug-clear-malloc7SuccessMon Aug 13 06:07:51 20072014
cm64SuccessThu Aug 16 04:53:23 2007430
cm64-debugSuccessTue Aug 7 06:30:13 20072055
cmSuccessWed Mar 4 01:24:58 200948
cm-debugSuccessMon Mar 2 02:18:39 2009522
cm64SuccessWed Mar 4 01:25:00 200947
cm64-debugSuccessTue Mar 3 02:11:46 2009517
cmSuccessSun Mar 6 00:36:16 20161657
cm-debugSuccessSat Mar 5 00:46:32 20162108

Testing status by file:

Html last generated: Sun Mar 6 05:51:37 2016

Input last modified: Tue Jun 20 11:22:41 2006

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