A computational fluid dynamics (CFD) is coupled with a computational structural dynamics (CSD) to simulate the unsteady rotor flow with aeroelasticity effects. An unstructured upwind Navier-Stokes solver was developed for this simulation, with 2nd order time-accurate dual-time stepping method for temporal discretization and low Mach number preconditioning method. For turbulent flows, both the Spalart-Allmaras and Menter's SST model are available. Mesh deformation is achieved through a fast dynamic grid method called Delaunay graph map method for unsteady flow simulation. The rotor blades are modeled as Hodges & Dowell's nonlinear beams coupled flap-lag-torsion. The rotorcraft computational structural dynamics code employs the 15-dof beam finite element formulation for modeling. The structure code was validated by comparing the natural frequencies of a rotor model with UMARC. The flow and structure codes are coupled tightly with information exchange several times at every time step. A rotor blade model's unsteady flow field in the hover mode is simulated using the coupling method. Effect of blade elasticity with aerodynamic loads was compared with rigid blade.
[1]
Jonathan Weiss,et al.
Preconditioning Applied to Variable and Constant Density Time-Accurate Flows on Unstructured Meshes
,
1994
.
[2]
Ning Qin,et al.
Fast dynamic grid deformation based on Delaunay graph mapping
,
2006
.
[3]
Earl H. Dowell,et al.
Nonlinear equations of motion for the elastic bending and torsion of twisted nonuniform rotor blades
,
1974
.
[4]
Hubert Pomin,et al.
Aeroelastic Analysis of Helicopter Rotor Blades on Deformable Chimera Grids
,
2004
.
[5]
Inderjit Chopra,et al.
Finite Element Analysis for Bearingless Rotor Blade Aeroelasticity
,
1984
.
[6]
Elizabeth M. Lee-Rausch,et al.
Rotor Airloads Prediction Using Unstructured Meshes and Loose CFD/CSD Coupling
,
2008
.