Mesh for the 3d-Gurney

In the three-dimensional simulations the mesh consists of 40 layers of the original 2d mesh covering $b=2h$ in the spanwise direction and has about $1.6 \times 10^6$ nodes. For the DES the same three-dimensional mesh can be applied as it is designed with respect to Spalart's guidelines for DES-meshes [19].

The three-dimensional investigations include Gurney-flaps with slits (3d Gurney, see fig. , right). Such configurations have been successfully applied in experimental studies [7].

Depending on the boundary condition that is prescribed at the Gurney-flap surface the same mesh can be used for 2d Gurneys as well as for those with small slits of width $0.2h$ that are located with a clearance of $2h$. As the complete Gurney-flap without the trailing edge of the airfoil is slitted, each slit has a depth of $0.66h$.

Figure: Left: three-dimensional sketch of the Gurney-flap (2d Gurney); right: sketch of the Gurney-flap with slits (3d Gurney).