Title of Dissertation: On Overset Grids Connectivity and Vortex Tracking in Rotorcraft CFD YikLoon Lee, Doctor of Philosophy, 2008 Dissertation directed by: Associate Professor James D. Baeder Department of Aerospace Engineering Two new numerical techniques that are useful in the simulation of high fidelity, vortical interactional aerodynamics for rotorcraft are developed. The first is a simple...

We present a study of the dynamics of passive wing-pitching in flapping-wing hovering flight, employing an integrated simulation approach. Here, the motion of a perfectly rigid wing is described using the Euler-Lagrange equation in Kane’s formulation, in which the passive rotating mechanism (flexure hinge) is modeled as a single-axis elastic beam and the total aerodynamic moment is computed by ...

A numerical model for shallow-water equations has been built and tested on the Yin–Yang overset spherical grid. A high-order multimoment finite-volume method is used for the spatial discretization in which two kinds of so-called moments of the physical field [i.e., the volume integrated average (VIA) and the point value (PV)] are treated as the model variables and updated separately in time. In...

A coupling method based on the overset grid approach has been successfully developed to couple multi-copies of a massively-parallel unstructured compressible LES solver AVBP for turbomachinery applications. As proper LES predictions require minimizing artificial dissipation as well as dispersion of turbulent structures, the numerical treatment of the moving interface between stationary and rota...

A new numerical approach for simulating nonlinear wavepackets in hypersonic boundary-layers is presented. The adaptive mesh refinement wavepacket tracking (AMR-WPT) method has been developed as an efficient alternative to conventional direct simulations (DNS). AMR-WPT employs the disturbances equations (NLDE), overset dual with higher-order interpolation, and (AMR) track boundary-layer flows. A...

Recent developments in three pieces of software for performing pre-processing and post-processing work on numerical computations using overset grids are presented. The first is the OVERGRID graphical interface which provides a unified environment for the visualization, manipulation, generation and diagnostics of geometry and grids. Modules are also available for automatic boundary conditions de...

A scheme is described for the automatic domain decomposition and creation of overset grids around surface discontinuities. Curves along surface discontinuities are called seam curves. The seam curves are rst automatically extracted from a multiple panel network description of the surface. Points where three or more seam curves meet are automatically identied and are called seam corners. Surface...

An algorithm for surface domain decomposition and grid generation for overset grids is described. A complex surface domain is covered by two types of grids: seam grids and block grids. Seam grids are grids used to wrap around surface crease lines and regions of high surface curvature. Block grids are grids that cover the remaining surface regions not occupied by the seam grids. The seam and blo...