A numerical study of flow fields in a branching tube

An effective and reliable numerical method is developed to solve the three-dimensional incompressible Navier-Stokes equations and to investigate fluid flows in three-dimensional branching tubes. The proposed numerical method is developed by the artificial compressible method. It uses a third-order upwind finite volume method to discretize convection terms and a second-order finite volume to discretize viscous terms. A diagonal dominated alternating direction implicit scheme (DDADI) coupling with an implicit residual smoothing is used to achieve a larger CFL number for time marching. The fluid flows in Y-shape and T-shape tubes are simulated. The effects of Reynolds number, branching flow ratio, branching angle, and comer type of branching tube on flow field behaviors are investigated. The vortex length and circulation zone are also discussed.