260
8. Complex Geometries
Flow
Fig. 8.16. Geometry and boundary conditions for laminar flow around a circular
cylinder in a channel
Fig. 8.17. The level two grid, used to calculate 2D flow around a circular cylinder
in a channel (5000 CVs; only part of the grid is shown)
Cd,,,,
Extrapolated value: 5.581
Extrapolated value: 3.228
5 . 5 4 4
J . l /
1
2
3
4
i 1 2 3
4
Grid level
Grid level
Fig. 8.18. Drag coefficients for the 2D flow around a cylinder in a channel as
functions of grid size: steady flow at Re = 20 (left) and the maximum drag coefficient
in a periodic unsteady flow at Re = 100 (right); from Muzaferija et al. (1995)
where fx and f, are the x and y component of the force exerted by the
fluid on the cylinder. This force is calculated by integrating the pressure and