A lot of computational codes for solving the compressible Navier-Stokes equations have been already developed for calculating 3-D transonic viscous flows over a wing. However, most of the codes have assumed flows as perfect gas without phase change. Since moist air involves a finite rate of vapor, it is occasionally condensed to liquid according to atmospheric weather conditions. It is known that the nonequilibrium condensation occurs over a wing in atmospheric wind tunnel conditions at transonic speed. It associates the release of latent heat due to the phase change from vapor to liquid and also it induces a condensation shock. The condensation results in temperature and pressure increases. Finally it affects the lift/drag ratio. We have developed a computational code for condensate flows over a wing. 3-D transonic condensate flows around the ONERA M6 wing has been calculated(１，２）.

Currently, we have extended this code to a code for condensate flows around NACA0012 airfoil and over a delta wing with heterogeneous nucleation assuming atmospheric flight conditions. The calculted results suggest that the condensation phanomena is quite different from the condensation in atmospheric wind tunnel conditions. The condensation over the delta wing occurs in a streamwise vortex because of a very low temperature at the core of vortex. The onset of condensation can start at a lower speed due to the effect of heterogeneous nucleation compared with that in atmospheric wind tunnel conditions(１，２).

References

Hideki HAGARI and Satoru YAMAMOTO, Numerical Investigation of Condensation Effect to Unsteady Transonic Viscous Flows in Moist Air, Proceedings of International Conference on Fluid Engineering, JSME Centennial Grand Congress, III (1997-7), 1701-1706.

S.Yamamoto and H. Hagari, Numerical Investigation of Nonequilibrium Condensation Effect around 3-D Transonic Wing in Moist Air, Proceedings of 16th International Conference on Numerical Methods in Fluid Dynamics, Lecture Notes in Physics, 515(1998), 554-559, Springer.

Satoru Yamamoto, Hideki Hagari and Mitsuhiro Murayama, Numerical Simulation of Condensation around the 3-D Wing, Transactions of the Japan Society for Aeronautical and Space Sciences, 42-138(2000).

Satoru Yamamoto, Onset of Condensation in Vortical Flow over Sharp-edged Delta Wing, AIAA Paper 2001-2651, (2001), also in AIAA Journal, 41-9(2003), 1832-1835.

Yasuhiro SASAO and Satoru YAMAMOTO, Numerical Prediction of Humid Effect to Transonic Flows in Turbomachinery, Proceedings of International Gas Turbine Congress 2003 Tokyo, (2003), CD-ROM.