7.8 Examples
207
grids. As test cases we choose two flows in square enclosures; one flow is driven
by a moving lid and the other by buoyancy. The geometry and boundary
conditions are shown schematically in Fig. 7.8. Both test cases have been
used by many authors and accurate solutions are available in the literature;
see Ghia et al. (1982) and Hortmann et al. (1990).
Moving lid uL
\
t
Adiabatic
Fig. 7.8. Geometry and boundary conditions for 2D flow test cases: lid-driven (left)
and buoyancy-driven (right) cavity flows
Fig. 7.9. A non-uniform grid with 32 x 32 CV used to solve the cavity flow
problems (left) and the streamlines of the lid-driven cavity flow at Re = 1000
(right), calculated on a 128 x 128 CV non-uniform grid (the mass flow between
any two adjacent streamlines is constant)
We first consider the lid-driven cavity flow. The moving lid creates a
strong vortex and a sequence of weaker vortices in the lower two corners.