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MODELING OF BLOOD FLOW THROUGH THE VEINS WITH COMPRESSION THERAPY
Poster P-103
S476
Modelling
MODELING OF BLOOD FLOW THROUGH THE VEINS WITH COMPRESSION THERAPY Nenad Filipovic(1)(2), Milos Kojic(1)(2)
1. University of Kragujevac, SERBIA; 2. Harvard School of Public Health, USA
Introduction In the human, the return of venous blood from the lower limbs to the heart requires the assistance of a pump structure equipped with non return valves. If the valves in the large veins become incompetent due to primary degeneration or post-thrombotic damage, blood will oscillate up and down in those segments lacking functional valves. Compression therapy is the principal therapy of veins with incompetent valves [Wertheim et al, 1999]. We proposed a computational model of blood flow through the veins with rigid and deformable walls as well as compression therapy effects.
completely open when the mean velocity near the valve is in the positive y direction, otherwise it is closed. In our model we introduce the percentage parameter which determines part of the closed cross-section when the valve is in the closed position.
Results The field of velocity magnitude at t=0.15[s] is shown in Fig. 2 for the following parameters: (lengths in [mm]) D=5, L=100, =0.5; E=3.61 [N/mm2], =0.49, w=1.1 [g/cm3]; domain of force action=30-70 [mm], compression forces =0-100 [N].
Methods Geometry of the straight axi-symmetric vein and data are shown in Fig. 1. The diameter D, length L, position and geometry of the valves define the basic geometry of the blood flow domain. Material data are blood density as well as dynamics viscosity . Additional parameters to take into account vein wall deformability in modeling blood flow are the wall thickness , Young’s module E, Poisson’s ratio and wall density w. The parabolic velocity profile is prescribed on the top of the model as a time function v(t), see Fig. 1.
Figure 2: Velocity distribution at t=0.15[s] (peak velocity) for blood flow through deformable vein with prescribed compression therapy force. Entering velocity profile is given in Fig. 1b. Velocities are 20% larger than in case when the compression therapy is not used [Filipovic et al, 2006, Kojic et al, 2008]
References Figure 1: Basic data for blood flow through a simple axi-symmetric vein with rigid and deformable walls. a) Geometrical data, FE mesh and boundary conditions; b) Prescribed velocity during one cycle T
Wertheim et al, Med. Biolog. Engrg Comp., 37, 3134,1999. Filipovic et al VEINS, Specialized CFD software for simulation of blood flow through the veins, University of Kragujevac, Serbia, 2006. Kojic et al, John Wiley & Sons, 2008 (to appear).
Valves move within the cycles and represent timedependent boundary for the blood flow. A valve is Journal of Biomechanics 41(S1)
16th ESB Congress, Posters
S476
Modelling
MODELING OF BLOOD FLOW THROUGH THE VEINS WITH COMPRESSION THERAPY Nenad Filipovic(1)(2), Milos Kojic(1)(2)
1. University of Kragujevac, SERBIA; 2. Harvard School of Public Health, USA
Introduction In the human, the return of venous blood from the lower limbs to the heart requires the assistance of a pump structure equipped with non return valves. If the valves in the large veins become incompetent due to primary degeneration or post-thrombotic damage, blood will oscillate up and down in those segments lacking functional valves. Compression therapy is the principal therapy of veins with incompetent valves [Wertheim et al, 1999]. We proposed a computational model of blood flow through the veins with rigid and deformable walls as well as compression therapy effects.
completely open when the mean velocity near the valve is in the positive y direction, otherwise it is closed. In our model we introduce the percentage parameter which determines part of the closed cross-section when the valve is in the closed position.
Results The field of velocity magnitude at t=0.15[s] is shown in Fig. 2 for the following parameters: (lengths in [mm]) D=5, L=100, =0.5; E=3.61 [N/mm2], =0.49, w=1.1 [g/cm3]; domain of force action=30-70 [mm], compression forces =0-100 [N].
Methods Geometry of the straight axi-symmetric vein and data are shown in Fig. 1. The diameter D, length L, position and geometry of the valves define the basic geometry of the blood flow domain. Material data are blood density as well as dynamics viscosity . Additional parameters to take into account vein wall deformability in modeling blood flow are the wall thickness , Young’s module E, Poisson’s ratio and wall density w. The parabolic velocity profile is prescribed on the top of the model as a time function v(t), see Fig. 1.
Figure 2: Velocity distribution at t=0.15[s] (peak velocity) for blood flow through deformable vein with prescribed compression therapy force. Entering velocity profile is given in Fig. 1b. Velocities are 20% larger than in case when the compression therapy is not used [Filipovic et al, 2006, Kojic et al, 2008]
References Figure 1: Basic data for blood flow through a simple axi-symmetric vein with rigid and deformable walls. a) Geometrical data, FE mesh and boundary conditions; b) Prescribed velocity during one cycle T
Wertheim et al, Med. Biolog. Engrg Comp., 37, 3134,1999. Filipovic et al VEINS, Specialized CFD software for simulation of blood flow through the veins, University of Kragujevac, Serbia, 2006. Kojic et al, John Wiley & Sons, 2008 (to appear).
Valves move within the cycles and represent timedependent boundary for the blood flow. A valve is Journal of Biomechanics 41(S1)
16th ESB Congress, Posters