Computational Simulation of the Urinary System

Recent advances in computational fluid dynamics (CFD), the availability of supercomputing power and the current understanding of the ureter make a realistic computational model of a ureter feasible. This study is aimed of developing a computational model of the ureter to examine urine flow. We use the in-house CFD code CgLes which is a highly parallelised three–dimensional fluid solver with second order accuracy in both time and space. It uses the Navier Stokes equations to simulate both laminar and turbulent incompressible flow of a fluid. The immersed boundary method has been implemented into CgLes to simulate moving boundaries and it will be used to simulate the interaction between the flow of urine and ureter. To simulate the wall of ureter, CgLes has been coupled with a world-class in-house Discrete Element Model (DEM) C code. An initial simulation has been carried out by applying a circumferential force to a flexible tube in two locations away from its inlet in order to simulate peristalsis motion. The tube was fixed at the inlet and outlet and we believe these deformations to be very similar to those of a real ureter. Further work will focus on the movement of urine down a ureter using the exact geometry from CT scans and the Mimics software.