Shock wave interacts with the droplets as a high-speed flight vehicle penetrates cloud or rain storm in the earth's atmosphere. Interaction of the shock with the gas-droplet two-phase medium significantly affects the aerodynamic performance of the flight vehicle. In the present paper, we investigate the aerodynamic field and wall variables as the moving shock wave diffracts over a wedge in the droplet-gas mixture. We used the compressible two-fluid model equations that have been solved by the HLL-based weighted average flux (WAF) method. The viscous drag force and the heat transfer terms have been included in the model to let the gas and the droplet phases interact. We investigate the effects of the three parameters associated with the microdroplets: the void fraction, the size and the material. We elaborate how the relaxation zone created by the shock wave diffraction is structured and changed in the droplet-gas mixture. (C) 2010 Elsevier Ltd. All rights reserved.