Unsteady flow in complex moving geometries


CFD can nowadays be used on a lot of steady-state flows, but simulating flows in domains with complex(ly) moving boundaries is still a difficult affair. Yet this kind of simulations are necessary as well. Although the performance of volumetric compressors and engines (piston compressors and engines, tooth compressors, screw compressors, ...) can be rather well predicted using 1d-models, the flow inside these machines is not very well understood. Due to the unsteady nature of volumetric compressors, their flow must be calculated in a time-dependent fashion.

Scope of research

This research aims to simulate flow inside complex moving geometries, using an ALE (Arbitrary Lagrangean Eulerean) solver. This solver will not be developed, but a commercial one will be used. This solver, however, as all solver codes, relies on a good quality calculation grid, but the movement of a domain boundary will usually severely distort the attached grid. A grid manipulation code must be added to the solver to ensure grid quality at each timestep. The objective of this research is the development of a grid-manipulator suitable for the 3d-simulation of complex geometries, such as tooth and screw compressors.


  • Two-dimensional incompressible Navier-Stokes calculations in complex-shaped moving domains K. Riemslagh, J. Vierendeels en E. Dick , J. Eng. Math., 34(1-2):57-73, 1998
  • A three-dimensional analysis of flow in the pivot regions of an ATS bileaflet valve S.G.D. Kelly, P.R. Verdonck, J.A.M. Vierendeels, K. Riemslagh, E. Dick en G.G. Van Nooten, Int. J. Artif. Org., 22(11):754-763, 1999
  • An arbitrary Lagrangian-Eulerian finite-volume method for the simulation of rotary displacement pump flow. K. Riemslagh, J. Vierendeels en E. Dick, Applied Numerical Mathematics, 32:419-433, 2000