An implicit hybrid method for the computation of rotorcraft flows

Abstract

There is a wide variety of CFD grid types including Cartesian, structured, unstructured and hybrids, as well as, numerous methodologies of combining these to reduce the time required to generate high-quality grids around complex configurations. If the grid methodologies were implemented in different codes, they should be written in such a way as to obtain the maximum performance from the available computer resources. A common interface should also be required to allow for ease of use. However, it is very time consuming to develop, maintain and add extra functionally to different codes. This paper examines the possibility of taking an existing CFD solver, the Helicopter Multi-Block (HMB) CFD method, and implementing a new grid type while reusing as much as possible the original code base. The paper presents some of the challenges encountered in extending the code which was written for a single mesh type, to a more flexible solver that is still computationally efficient but can cope with a variety of grid types.

Assessment of current rotor design comparison practices based on high-fidelity CFD methods

“…The linearised system of equations is solved using the Generalised Conjugate Gradient method with a Block Incomplete Lower-Upper (BILU) factorisation as a pre-conditioner (16) . To allow an easy sharing of the calculation load on parallel computers, multi-block structured meshes are used (17) .…”

Rotor-Blade Planform Design Based on an Overset Harmonic-Balance-Adjoint Optimization Framework

“…For all methods the linearised system of equations is solved using the Generalised Conjugate Gradient method with a Block Incomplete Lower-Upper (BILU) factorisation as a pre-conditioner [60]. To allow an easy sharing of the calculation load for parallel jobs, multi-block structured meshes are used [61]. For this study, the fully-turbulent Wilcox's k-ω-SST model from Menter [62] is employed.…”