Sliding Mesh Algorithm for CFD Analysis of Helicopter Rotor-Fuselage Aerodynamics

摘要

Difficulties associated with the numerical simulation of rotor-fuselage interactional aerodynamics stem from the flow complexity and the requirement for interfacing the rotor and fuselage domains in a numerically consistent fashion with minimal computational overhead. Efforts in this direction include adaptive re-meshing, within the context of unstructured grid solvers or the CHIMERA approach which is mainly associated with structured, multi-block meshes. Both techniques have been successfully demonstrated for the numerical simulation of helicopter flows and have provided significant insight in this complex flow. In this work, a different approach is used which is based on the sliding grid concept in an effort to reduce the computational overhead associated with rotor-body computations. To account for the relative motion between the fuselage and the rotor blades, a sliding interface is introduced. This forms a boundary between a CFD mesh around the fuselage and a rotor-fixed CFD mesh and allows communication between the two domains. Meshes adjacent to the sliding interface do not necessarily have matching nodes or even the same number of cell-faces. This leads to an interpolation problem, which i) should not introduce numerical artefacts, ii) should have minimal effects on the overall solution quality and iii) should have small CPU overhead. The sliding mesh methods developed for this work are demonstrated for two rotor-fuselage test cases. The first is the ROBIN body with the HIMARCS rotor as an example of a generic test case, while the second considers a realistic medium-weight helicopter wind tunnel model under investigation in the European Commission 6th Framework GOAHEAD project.