To overcome the difficulties in generating high quality integrative structured grids around the tiltrotor aircraft

the multiblock grid strategy and embedded grid method were combined to establish a new embedded grid generation method

which was suitable for aerodynamic interaction analyses of tiltrotor aircraft. On the basis of keeping the interpolation accuracy

the whole grid system composed of the multiblock grids was used to reduce the size of the grids. Firstly

the InverseMap method was introduced for auxiliary localization

and the new multidirectional projection method was proposed to ensure the continuity of the hole boundaries among the multiblock grids. Then

the independent embedded grid strategy was used in completing the combination of the airframe and background grids

and the assistant coordinates were adopted in the identification of the background boundary grids. Compressible RANS (Reynolds averaged NavierStokes) equations with SA(SpalartAllmaras) turbulence model were employed in the bodyfitted region

and Euler equations were chosen to simulate the background region. In the present method

the SPMD (single program

multiple data) model parallel acceleration technology was adopted to improve the computational efficiency. On this basis

Robin airframe was taken as the numerical example to verify the validity of the present CFD method. Then the interaction flowfields of tiltrotor aircraft in different modes were investigated emphatically

and several simulated results (special fountain effect phenomenon in hover

special flowfield in conversion mode

and variations of the aerodynamic characteristics of the tiltrotor aircraft in cruise) were obtained. The proposed embedded grid method and the numerical method were demonstrated to be effective in investigating the aerodynamic configuration of the tiltrotor aircraft

laying a good foundation for analyzing aerodynamic characteristics of the tiltrotor aircraft

with the speedup greater than 50.