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Unsteady flow calculations with a multiblock moving mesh algorithm
 AIAA Journal
"... An eective dynamic moving mesh algorithm suitable for multiblock parallel unsteady
ow calculations using body tted grids is presented in this paper. The moving grid algorithm within each block uses a method of arclength based transnite interpolation which is performed independently on local proces ..."
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An eective dynamic moving mesh algorithm suitable for multiblock parallel unsteady
ow calculations using body tted grids is presented in this paper. The moving grid algorithm within each block uses a method of arclength based transnite interpolation which is performed independently on local processors where the blocks reside. A spring network approach is used to determine the motion of the corner points of the blocks which may be connected in an unstructured fashion in a general multiblock method. A smoothing operator is applied to the points of the block face boundaries and edges in order to maintain grid smoothness and grid angles. A multiblock parallel Euler/NavierStokes solver using multigrid and dualtime stepping is developed along with the moving mesh method. Computational results are presented for the unsteady
ow calculations of airfoils and wings with deforming shapes as found in
utter simulations. 1
Static AeroElastic Computation with a Coupled CFD
 and CSD Method,” AIAA, 39th AIAA Aerospace Sciences Meeting and Exhibit, Paper
, 2001
"... The objective of this paper is to assess the computational eectiveness of an integrated scheme for static aeroelastic problems that makes use of methods of Computational Fluid Dynamics (CFD) and Computational Structural Dynamics (CSD). The CFD algorithm is based on an unsteady, parallel, multibloc ..."
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The objective of this paper is to assess the computational eectiveness of an integrated scheme for static aeroelastic problems that makes use of methods of Computational Fluid Dynamics (CFD) and Computational Structural Dynamics (CSD). The CFD algorithm is based on an unsteady, parallel, multiblock, multigrid nitevolume, Euler/NavierStokes solver previously used for time accurate unsteady
ow computations. This is coupled with a structures solver and a deforming mesh algorithm in time using a fully implicit dualtime stepping method. Grid deformation cost is small by using algebraic techniques. The computational eort needed for updating the aerodynamic shape due to elastic deformation is rendered negligible by using modal approximations predetermined by using a nite element method or experimentally. Since time accuracy is irrelevant, static elastic equations are used rather than the dynamic structural equations. The structural and
ow equations interact at every iteration in time. For illustrative purposes a generic wing was studied using both Euler and NavierStokes computations. Results show that computational cost of this method is comparable to a CFD study of a rigid structure. Comparisons are made of computed pressure distributions for the rigid and exible wings at the same
ight conditions. Comparisons are also made between the results of Euler and NavierStokes computations. I.
NavierStokes Simulation of 2D Unsteady Aerodynamics of a Turbine Cascade
, 2001
"... A NavierStokes solver coupled with the kω turbulence model is developed to solve the unsteady flow through an oscillating turbine cascade. Calculations are performed in parallel in a timeaccurate manner. A coupled simulation is performed for the Isogai wing model. ..."
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A NavierStokes solver coupled with the kω turbulence model is developed to solve the unsteady flow through an oscillating turbine cascade. Calculations are performed in parallel in a timeaccurate manner. A coupled simulation is performed for the Isogai wing model.
Key Word: Unsteady Flows
"... Flutter simulation of a transonic wing has been presented using a moving grid system. At first, a NavierStokes code has been validated by comparing computed solutions with experimental data for the oscillatory motion of rectangular wing. Then, flutter simulation of a highaspectratio swept back wi ..."
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Flutter simulation of a transonic wing has been presented using a moving grid system. At first, a NavierStokes code has been validated by comparing computed solutions with experimental data for the oscillatory motion of rectangular wing. Then, flutter simulation of a highaspectratio swept back wing has been presented. Aeroelastic responses are computed using the modal analysis based on the finiteelement method. The computed flutter boundaries are obtained and compared with NAL (National Aerospace Laboratory) flutter tunnel test.
Flutter Predictions by a Filtered Impulse Method
"... The indicial response method is a fast tool for calculating the dynamic response of an aerodynamic system that can be used for
utter predictions based on methods on the frequency domain. The conventional way of calculating the indicial response by using a step function or impulse function inputs ha ..."
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The indicial response method is a fast tool for calculating the dynamic response of an aerodynamic system that can be used for
utter predictions based on methods on the frequency domain. The conventional way of calculating the indicial response by using a step function or impulse function inputs has diculties in practical application when a CFD method is used to calculate the response because of the nonsmooth nature of the input functions. Three input functions that avoid potential nonphysical responses while at the same time provides adequate resolution for frequencies of interest of a given aeroelastic system are studied with a model dynamic system and a twodimensional wing model. The important parameters for accuracy and eciency in the numerical calculation of the frequency response by the indicial method are discussed. Guidance is given on the choice of time step size and integration length as well as the eect of the power spectrum of the input functions. I. Nomenclature c airfoil chord length. U1 freestream velocity.! lowest angular frequency of interest.! dimensionless angular frequency based