Eventos Anais de eventos
COBEM 2017
24th ABCM International Congress of Mechanical Engineering
Implementation of a Jacobian-free method for the instability analysis of a compressible flow over an open cavity
Submission Author:
Marlon Sproesser Mathias , SP
Co-Authors:
Marcello Augusto Faraco de Medeiros, Vassilios Theofilis, Marlon Sproesser Mathias
Presenter: Marcello Augusto Faraco de Medeiros
doi://10.26678/ABCM.COBEM2017.COB17-2889
Abstract
An algorithm based on the Arnoldi iteration is implemented to compute the instability modes of a compressible flow over an open cavity. The flow is solved by a Direct Numerical Solver (DNS), which uses high-order spectral-like numerical differentiation methods. This allows shorter wavelengths to be resolved without further refining the mesh, reducing the computational cost. To further speed-up the execution, the code is run in parallel by a domain decomposition technique. The instability analysis is based on the Arnoldi iteration method, with is directly linked to the DNS, causing this to be a very modular and flexible strategy, as the flow solver may be replaced with only minor changes to the rest of the code. The purpose of this work is to implement this algorithm for a subsonic compressible flow. Numerical parameters of the algorithms and their trade-offs are analyzed. For example, longer run times at each DNS call cause the Arnoldi to converge faster and vice-versa. The goal is to produce reliable results while reducing memory requirements and processing time.
Keywords
Open cavity flow, direct numerical simulation, Hydrodynamic Instability, Compressible flow, Arnoldi iteration.
