This Note considers the generalization of a transformation method for passing information between structural and aerodynamic surface grids for aeroelastic simulation. The initial method, the constant-volume-tetrahedron (CVT) scheme, was developed for isolated aircraft components. In CVT, a surface element consisting of the three nearest structural grid points to a given fluid grid point is identified. Once these structural grid points are identified, the associated fluid grid point can be described as a linear combination of three basis vectors, two of them being parallel and one unit being perpendicular to the surface of the structure. As the structure deforms, i.e. the locations of the structural grid points change, the location of the fluid grid point is recalculated with the assumption that only the out-of-plane component changes. This method has been extended to consider multiple connected components by allowing different parts of the structural model to drive the fluid surfaces in a hierarchical manner. The fluid and structural grid points on the fuselage are designated as being of level 1, structural grid points on the wings, tail planes and fins are designated level 2, and extra components attached to the wing, such as fuel tanks and stores, are designated level 3. The idea of this hierarchy is that, for example, level 2 points have a primary motion because they are connected to the fuselage and secondary motion caused by their own elasticity. A problem with the level 2 mapping arises at junctions between components, because mapping the nodes off the fuselage are being driven by different components in the structural model from those actually on the junction, which are driven by the fuselage. This leads to a small but disastrous distortion of the grid in the junction region. Therefore, the resulting fluid and structure positions are blended to ensure that different parts of the fluid surface mesh remain attached.
Intergrid transformation for aircraft aerolastic simulations
Transformation von Gitternetzen zur aeroelastischen Simulation von Flugzeugen
AIAA Journal ; 42 , 9 ; 1936-1939
2004
4 Seiten, 4 Bilder, 9 Quellen
Aufsatz (Zeitschrift)
Englisch
INNOVATIVE AIRCRAFT AEROLASTIC MODELLING AND CONTROL
British Library Conference Proceedings | 2010
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