Wing-Body-Pylon-Nacelle Configuration

Figure 7: WBPN: Surface pressure distribution and streamlines

This geometry (WBPN), which has been a mandatory testcase in the European validation project AVTAC [19], is presented to demonstrate the applicability of the advanced turbulence models to configurations of practical interest. Results are reported for typical transonic conditions, the inflow is set to $Ma=0.8$, $Re=10.8\cdot10^{6}$ per meter and $\alpha=2.2^{\circ}$. A grid supplied by Airbus Germany consisting of approximately 5.3 million nodes and 78 blocks largely varying in size is employed. A $y^{+}\approx1$ can be kept over most parts of the geometry, only in the rear part of the fuselage higher $y^{+}$ have to be tolerated. The results are obtained with FLOWer using LEA $k$-$\omega$, computations by Airbus Germany with FLOWer and Wilcox $k$-$\omega$ as well as L-EARSM + Wilcox $k$-$\omega$ from [19] are included for comparison. Owing to the rather complex geometry, no transition is set.

The surface pressure distribution and the streamlines, see Fig. 7, show a strong shock on the suction side of the wing, however, the flow does not separate. Furthermore, the influence of the pylon and the nacelle on the shock structure are clearly visible. Turning the attention to the pressure distribution in selected wing sections, Fig. 8, a generally good agreement with the experiment can be seen. LEA $k$-$\omega$ determines the shock slightly upstream of L-EARSM + Wilcox $k$-$\omega$ while Wilcox $k$-$\omega$ predicts a shock location downstream of the linearized EASM. However, the differences remain small, hinting at a weak shock-boundary-layer interaction. This is confirmed by the flow remaining attached over the whole suction side of the wing.

Figure 8: WBPN: Pressure distribution in selected wing sections, comparison with data from Airbus Germany (A)