Nested grids using patched grid generation technique and characteristics computation of variable forwardswept wing

In order to efficiently predict the controllability of split rudder with Variable Forwards Swept Wing (VFSW) efficiently, a nested grids method using patched-grids generation technique was developed. The flux conservation on both sides of the interface was established by air-weight mean method. N-S equation, as the governing equation, were solved numerically using finite volume method with SST turbulence model. The lift-drag ratio of airfoil NACA 23012 with wing flap deflection of 30° was simulated, whose results were compared with those in normal block grids, as well as those of wind tunnel experiments. The example showed that the Mach cloud picture and the separation point position of airflow on upper surface of wing flap of nested grids are the same with that of common grids. Both have the trend to genverate a vortex under the airfoil. The patched-grid generation technique and air-weight mean method ensured the flux conservation transmission and computational precision, which is simple, convenient and efficient. Finally, the lift-drag ratio of split rudders in VFSW configuration was computed, and the airflow moved from wing tip to wing root on forwards swept wing, which avoided a sharp decline in control efficiency caused by losing speed about wing tip in advance. The nested grids method using patched-grids generation technique worked well in the calculation of VFSW performance and the results showed the nested grids method had a high efficiency in control surface design and performance computation.