Transonic Transport Research Articles

Navier-Stokes simulations of transonic flows over a wing-fuselage combination

Computations of transonic flows over a practical wing-fuselage geometry designed for a transonic transport aircraft are carried out using three-dimensional Reynolds-averaged Navier-Stokes equations. The thin-layer approximation is extended to two directions to evaluate viscous layers on both the wing and fuselage surfaces. The LU-ADI factorization algorithm is used with the implementation of new smoothing terms. Computations are done for several angles of attack with the specified Mach and Reynolds numbers corresponding to the experiment, and the comparison of the computed surface pressure to the experimental data shows good agreement. The computed results reveal the effect of the fuselage near the wing root, especially at relatively high angles of attack. It is shown that the flow pattern when a fuselage exists is quite different from that for an isolated wing. This indicates the importance of the computation over a wing-fuselage combination using Navier-Stokes equations. The computations, which uses about 700,000 grid points, requires about 5-6 h of computer time on a Japanese supercomputer for each case.

Aerodynamic investigations toward an adaptive airfoil for a transonic transport aircraft

Drag reduction and the extension of the flight region with high aerodynamic efficiency for transonic airfoils has been investigated by applying the idea of an adaptive airfoil. With the aid of the elliptic continuation method, a basic airfoil has been optimized with regard to shock-free pressure distributions for three different flow conditions (A/,c/). The three resulting airfoils, representing operating points of an adaptive airfoil, have been investigated numerically and in wind tunnel tests. The results indicate that high aerodynamic efficiencies are connected with pressure distributions having already weak shock waves. Furthermore, the anticipated extension of the flight region with high aerodynamic efficiency by applying an adaptive airfoil could not be verified for all flight conditions.

遷音速翼の空力設計例とその風試結果

遷音速翼の空力設計例とその風試結果

Application of NLR's calculation methods to transonic flow about oscillating wings

Unsteady and quasisteady aerodynamic loads in the transonic flow domain have been obtained from the numerical simulation methods of the National Aerospace Laboratory (NLR) for transonic potential flow. The unsteady results have been obtained with the time-linearized finite volume method FTRAN3, embedding a socalled field panel method which accounts for proper radiation of signals toward infinity. The mean steady flowfields and the quasisteady results have been obtained from the application of XFLO22—the NLR system for the simulation of steady transonic flow about wings and wing bodies. The calculations have been performed for several wing planforms and the results are compared with experimental data. A correlation is made between the quasisteady results of XFLO22 and FTRAN3. Flutter applications to a transonic transport wing model and a fighter configuration have been made.