Computation of incompressible viscous flows through artificial heart devices with moving boundaries

Abstract

The current work illustrates the extension of computational fluid dynamics techniques to artificial heart flow simulation. Unsteady incompressible Navier-Stokes equations written in three-dimensional generalized curvilinear coordinates are solved iteratively at each physical time step until the incompressibility condition is satisfied. The solution method is based on the pseudo-compressibility approach and uses an impllcit-upwind differencing scheme together with the Gauss-Seidel line relaxation method. The efficiency and robustness of the time-accurate formulation of the numerical algorithm are tested by computing the flow through model geometries. A channel flow with a moving indentation is computed and validated with experimental measurements and other numerical solutions. In order to handle the geometric complexity and the moving boundary problems, a zonal method and an overlapped grid embedding scheme are employed, respectively. Steady-state solutions for the flow through a tilting-disk heart valve are compared against experimental measurements. Good agreement is obtained. The flow computation during the valve opening and closing is carried out to illustrate the moving boundary capability. Aided by experimental evidence, the flow through an entire Penn State artificial heart model is computed.

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