Design of a laminar wing for a commuter airplane using a 3D-design method

Summary

Using conventional design methods a laminar wing was designed for the DO 328 commuter airplane in a preceding work. However, in the vicinity of the body and the nacelle, strong interference effects diminished the extent of laminar flow. In this work a 3D design method based on the solution of the Euler equations was used to enlarge the extent of laminar flow for the wing region placed nearby nacelle and body. In order to solve numerically the Euler equations, a structured 3D computational mesh was generated around the wing, nacelle and body of the DO 328 configuration. For the design task it was necessary to elaborate a design procedure which retained the original wing twist distribution and wing thickness in the spar region. In addition to the geometrical constraints, the lift values were prescribed at the design points being the maximum cruise and climb flight conditions. Using the laminar wing of the preceding work as starting condition, a new wing was designed with improved stability results of the laminar boundary layer for the aforementioned design points. Improvements were obtained especially in the regions near to the nacelle and the body.