Extension of a discontinuous Galerkin finite element method to viscous rotor flow simulations

Heavy vibratory loading of rotorcraft is relevant for many operational aspects of helicopters, such as the structural life span of (rotating) components, operational availability, the pilot's comfort, and the effectiveness of weapon targeting systems. A precise understanding of the source of these vibrational loads has important consequences in these application areas. Moreover, in order to exploit the full potential offered by new vibration reduction technologies, current analysis tools need to be improved with respect to the level of physical modeling of flow phenomena which contribute to the vibratory loads. In this paper, a computational fluid dynamics tool for rotorcraft simulations based on first-principles flow physics is extended to enable the simulation of viscous flows. Viscous effects play a significant role in the aerodynamics of helicopter rotors in high-speed flight. The new model is applied to three-dimensional vortex flow and laminar dynamic stall. The applications clearly demonstrate the capability of the new model to perform on deforming and adaptive meshes. This capability is essential for rotor simulations to accomodate the blade motions and to enhance vortex resolution

Extension of the discontinuous Galerkin finite element method to viscous rotor flow simulations

Heavy vibratory loading of rotorcraft is relevant for many operational aspects of helicopters, such as the structural life span of (rotating) components, op- erational availability, the pilot’s comfort, and the ef- fectiveness of weapon targeting systems. A precise understanding of the source of these vibrational loads has important consequences in these application ar- eas. Moreover, in order to exploit the full poten- tial offered by new vibration reduction technologies, current analysis tools need to be improved with re- spect to the level of physical modeling of flow phe- nomena which contribute to the vibratory loads. In this paper, a computational fluid dynamics tool for rotorcraft simulations based on first-principles flow physics is extended to enable the simulation of vis- cous flows. Viscous effects play a significant role in the aerodynamics of helicopter rotors in high-speed flight. The new model is applied to three-dimensional vortex flow and laminar dynamic stall. The applica- tions clearly demonstrate the capability of the new model to perform on deforming and adaptive meshes. This capability is essential for rotor simulations to accomodate the blade motions and to enhance vor- tex resolution

Accurate computation of drag for a wing/body configuration using multi-block, structered-grid CFD technology

In this report the contribution of the National Aerospace Laboratory NLR to the ’CFD Drag Pre- diction Workshop’ organized by the AIAA in Anaheim, CA, on June 9-10, 2001, is presented. This contribution consists of both the results of all test cases and a discussion on the accurate computation of drag coefficients. Two approaches are presented and discussed. The first method performs a grid convergence study using a sequence of nested grids yielding the grid-converged drag coefficient. To enable this study to be carried out, such a sequence of nested multi-block structured grids (’NLR’ grid) has been generated. The second method, using one grid only, de- composes the drag coefficient into its ’physical components’ (vortex, wave and viscous drag). As a consequence, this method provides the aerodynamic designer with a helpful tool, because of its diagnostic potential

Discontinuous Galerkin finite element methods for hyperbolic differential equations

In this paper a suryey is given of the important steps in the development of discontinuous Galerkin finite element methods for hyperbolic partial differential equations. Special attention is paid to the application of the discontinuous Galerkin method to the solution of the Euler equations of gas dynamics in time-dependent flows domains and to techniques which reduce the computational complexity of the DG method