Navier-Stokes calculation of aerodynamic characteristics of wings in vortex wake encounter

摘要

A thin-layer Navier-Stokes method is used to calculate the asymmetric flow field of wings immersed in the vortex wake. ^Simulation of the experiment of El-Ramly et al. ^(1976) in a small tunnel with the following model located at five generating wing spans downstream shows fair agreement with experimental data in rolling moment. ^The in-tunnel simulation also indicates that the vortex location is more upward, and its strength is higher when compared with the free-air calculation. ^A numerical simulation of the experimental set-up of Rossow et al. ^(1975) with the following wing located at 13.3 generating-wing spans downstream shows that the computed rolling moment coefficients are much lower than the experimental data. ^The inaccurate results are due to weak predicted vortices which move away in the far wake from the region where the grid points are clustered, resulting in inadequate vortex flow resolution. ^Calculated results indicate that the induced maximum rolling moment with the model in a large tunnel is still much higher than that in free air. ^It is also found that the vortex-induced lift coefficient of the following wing is not significantly affected by the angle of attack of the following wing. ^(Author)