• Tomáš Neustupa Czech Technical University in Prague, Faculty of Mechanical Engineering, Karlovo nám. 13, 121 35 Praha 2, Czech Republic
  • Ondřej Winter Czech Technical University in Prague, Faculty of Mechanical Engineering, Karlovo nám. 13, 121 35 Praha 2, Czech Republic




Navier-Stokes equations, natural outlet boundary condition, finite volume method


This paper studies the artificial outflow boundary condition for the Navier-Stokes system. This type of condition is widely used and it is therefore very important to study its influence on a numerical solution of the corresponding boundary-value problem. We particularly focus on the role of the coefficient in front of the nonlinear term in the boundary condition on the outflow. The influence of this term is examined numerically, comparing the obtained results in a close neighbourhood of the outflow. The numerical experiment is carried out for a fluid flow through the channel with so called sudden extension. Presented numerical results are obtained by means of the OpenFOAM toolbox. They confirm that the kinetic energy of the flow in the channel can be controlled by means of the proposed boundary condition.


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