A simple and conservative unstructured sliding-mesh approach for rotor-fuselage aerodynamic interaction simulation

A conservative unstructured sliding-mesh technique is developed for the rotor-fuselage aerodynamic interaction simulation. The computational domain is decomposed into a rotational zone and a stationary zone. The rotational zone contains the rotor blades that rotate with the zone, while the stationary zone contains the fuselage which keeps stationary during the simulation. The two zones are connected via a sliding interface, which is designed to be a cylindrical surface consisting of the top, bottom, and side surfaces. The top and bottom surfaces are paved with arbitrary triangles and the side surface is meshed by triangularizing equal-sized and right-angled quadrilaterals. The intersection information between the rotational and stationary sliding interface meshes, such as the number of intersection triangles and the area of each intersection polygon, is the key to the present conservative computation. For the top and bottom surfaces, the point-on-line cases are first identified and the point perturbation operation is carried out to eliminate the potential error due to the presence of a point-on-line case. The neighbor-to-neighbor searching algorithm is applied for efficient determination of the intersection triangles, and the intersection polygon areas are determined by enumerating all the possible intersection cases. For the side surface, the intersection relations and polygon areas can be easily determined based on the enumeration method due to the special triangularization. The present method is validated by simulating the GIT (Georgia Institute of Technology) rotor-fuselage interaction model, and comparing numerical results with experiment measurements. It is demonstrated that the present conservative sliding-mesh method is simple to implement, and is efficient for the prediction of complicated unsteady rotor-fuselage aerodynamic interaction.