Peristalsis in Ureter
Proceedings of the 29th Annual International Conference of the IEEE EMBS Cité Internationale, Lyon, France August 23-26, 2007.
ThP2D2.8
A Numerical Simulation of Peristaltic motion in the Ureter Using Fluid Structure Interactions
Bahman Vahidi and Nasser Fatouraee of the muscle depends on the load against which it is contracting as well as on its current geometry and its state of activation, and that load consists largely of the hydrodynamic (viscous) forces required to move the urine. A theoretical analysis and numerical solutions were reported for peristaltic flow through a distensible tube of limited length [5]. Their results showed that in flow with isolated boluses, the pressure/flow relation was determined by the active and passive properties of the tube undergoing peristalsis and not by the outlet. Dynamics of the upper urinary tract and the effect of variations of bladder pressure on pyeloureteral pressure/flow relations have been studied by many researchers [6] but none of them included wall properties in their studies. Here an axisymmetric non-linear FSI model using ureteral real data is presented. II. THEORY A. The Fluid Model We consider transient viscous flow in an axisymmetric tube (Fig.1.). The flow is assumed to be laminar, Newtonian, viscous and incompressible. The incompressible NavierStokes equations are used as the governing equations. For boundary conditions, we assume that the tube have no axial motion, that no slipping takes place between the fluid and the wall and that no penetration of the fluid through the tube wall occurs. The pressures at the inlet and outlet of the tube are prescribed. This yields the following:
Abstract—An axisymmetric model with fluid-structure interactions (FSI) is introduced and solved to perform ureter flow and stress analysis. The Navier-Stokes equations are solved for the fluid and a linear elastic model for ureter is used. The finite element equations for both the structure and the fluid were solved
ThP2D2.8
A Numerical Simulation of Peristaltic motion in the Ureter Using Fluid Structure Interactions
Bahman Vahidi and Nasser Fatouraee of the muscle depends on the load against which it is contracting as well as on its current geometry and its state of activation, and that load consists largely of the hydrodynamic (viscous) forces required to move the urine. A theoretical analysis and numerical solutions were reported for peristaltic flow through a distensible tube of limited length [5]. Their results showed that in flow with isolated boluses, the pressure/flow relation was determined by the active and passive properties of the tube undergoing peristalsis and not by the outlet. Dynamics of the upper urinary tract and the effect of variations of bladder pressure on pyeloureteral pressure/flow relations have been studied by many researchers [6] but none of them included wall properties in their studies. Here an axisymmetric non-linear FSI model using ureteral real data is presented. II. THEORY A. The Fluid Model We consider transient viscous flow in an axisymmetric tube (Fig.1.). The flow is assumed to be laminar, Newtonian, viscous and incompressible. The incompressible NavierStokes equations are used as the governing equations. For boundary conditions, we assume that the tube have no axial motion, that no slipping takes place between the fluid and the wall and that no penetration of the fluid through the tube wall occurs. The pressures at the inlet and outlet of the tube are prescribed. This yields the following:
Abstract—An axisymmetric model with fluid-structure interactions (FSI) is introduced and solved to perform ureter flow and stress analysis. The Navier-Stokes equations are solved for the fluid and a linear elastic model for ureter is used. The finite element equations for both the structure and the fluid were solved
References: [1] [2] [3] S . Boyarsky, Acad. Press, N. Y., 1971. A. A. Bykova, and S.A. Regirer, “Mathematical Models in Urinary System Mechanics (review),” Fluid Dynamics, Vol. 40, No. 1, pp. 221-226, 2005. E. O. Carew, and T. J. Pedley, “An active membrane model for peristaltic pumping. Pt 1. Periodic activation waves in an infinite tube,” Trans. ASME: J. Biomech. Engng, Vol. 119, No. 1, pp. 66-76, 1997. A. A. Bykova, and S.A. Regirer, “Simple model of peristalsis in a myogenically-active tube,” Euromech. Colloquium 389, Book Abstrs, Graz, pp. 68-69, 1999. D. J. Griffiths, “Dynamics of the Upper Urinary Tract: I. Peristaltic Flow Through a Distensible Tube of Limited Length,” Phys. Med. Biol., Vol. 32, No. 7, pp. 813-822, 1987. D. J. Griffiths, C.E. Constantinou, J. Mortensen, and J.C. Djurhuus, “Dynamics of the Upper Urinary Tract: II. The Effect of Variations of Peristaltic Frequency and Bladder Pressure on Pyeloureteral Pressure/Flow Relations,” Phys. Med. Biol., Vol. 32, No. 7, pp. 823833, 1987. K. J. Bathe, Finite Element Procedures, Prentice Hall, New Jersey, 1996. K. J. Bathe, Theory and Modeling Guide, Vol I: ADINA, ADINA R & D, Inc., Watertown, MA, 2002. K. J. Bathe, Theory and Modeling Guide, Vol III: ADINA-F, ADINA R & D, Inc., Watertown, MA, 2002. [4] [5] [6] [7] [8] [9] 1171