A coupled BEM and arbitrary Lagrangian-Eulerian FEM model for the solution of two-dimensional laminar flows in external flow fields

摘要

This paper describes a new computational model developed to solve two-dimensional incompressible viscous flow problems in external flow fields. The model based on the Navier-Stokes equations in primitive variables is able to solve the infinite boundary value problems by extracting the boundary effects on a specified finite computational domain, using the pressure projection method. The external flow field is simulated using the boundary element method by solving a pressure Poisson equation that assumes the pressure as zero at the infinite boundary. The momentum equation of the flow motion is solved using the three-step finite element method. The arbitrary Lagrangian-Eulerian method is incorporated into the model, to solve the moving boundary problems. The present model is applied to simulate various external flow problems like flow across circular cylinder, acceleration and deceleration of the circular cylinder moving in a still fluid and vibration of the circular cylinder induced by the vortex shedding. The simulation results are found to be very reasonable and satisfactory.