Investigation of Transonic Drag Computations in Aerodynamic ...
Investigation of Transonic Drag Computations in Aerodynamic ...
Investigation of Transonic Drag Computations in Aerodynamic ...
Create successful ePaper yourself
Turn your PDF publications into a flip-book with our unique Google optimized e-Paper software.
<strong>Investigation</strong> <strong>of</strong> <strong>Transonic</strong> <strong>Drag</strong> <strong>Computations</strong> <strong>in</strong> APAS<br />
Area build-up graphs were also generated for the wave drag analyses <strong>of</strong> the 3<br />
RLV configurations. These configurations were not run <strong>in</strong> WAVDRAG, so no<br />
comparison was made with the APAS results. The APAS build-ups can be found <strong>in</strong><br />
Appendix B <strong>of</strong> this report.<br />
5.2 Wave <strong>Drag</strong> Comparisons<br />
The second and more conclusive comparison between APAS and WAVDRAG is<br />
that <strong>of</strong> the actual wave drag coefficients <strong>of</strong> each trial configuration generated by the two<br />
programs. Figure 45 shows the wave drag calculated by the wave subprogram <strong>of</strong> APAS<br />
and the results <strong>of</strong> the WAVDRAG analysis <strong>of</strong> the trial 1 configuration. Unlike APAS,<br />
WAVDRAG will generate results at Mach 1, but no lower.<br />
Trial 1<br />
C dw<br />
0.45<br />
0.4<br />
0.35<br />
0.3<br />
0.25<br />
0.2<br />
0.15<br />
0.1<br />
0.05<br />
0<br />
APAS Wavedrag<br />
WAVDRAG<br />
1 1.1 1.2 1.3 1.4 1.5 1.6<br />
Mach #<br />
Figure 45. Trial 1 Wave <strong>Drag</strong> Comparison<br />
WAVDRAG predicts a wave drag coefficient forty percent lower than APAS at<br />
Mach 1.01 due to the difference <strong>in</strong> the ways the programs calculate wave drag, one as<br />
zero-lift wave drag and the other as wave drag that <strong>in</strong>cludes that due to lift. The plots<br />
Jeff Miller 36
Change language