Eventos Anais de eventos
COBEM 2021
26th International Congress of Mechanical Engineering
NUMERICAL INVESTIGATION OF THE DESTRUCTIVE INTERFERENCE OF TWO NONLINEAR STANDING WAVES IN A DUCT
Submission Author:
Guilherme Mendes Santana , DF
Co-Authors:
Guilherme Mendes Santana, Roberto Miserda, Adriano Todorovic Fabro
Presenter: Guilherme Mendes Santana
doi://10.26678/ABCM.COBEM2021.COB2021-1806
Abstract
This work aims at investigating the interaction of high amplitude sound waves generated in opposing phases in a closed duct. This paper presents the results of four numerical studies of propagation and interaction of sound waves in a one-dimensional duct. These cases were studied via the numerical solution of the Euler equations for a compressible flow, with a finite volumes domain discretization, fluxes calculated with fourth-order precision, and a third-order Runge-Kutta scheme for the time march. The sound waves were generated by the movement of walls at the extremities of the domain. The boundary conditions were imposed with a moving-body, immersed-boundary method, and an interpolation inside the control volumes was proposed to properly capture the movement of the walls. The simulation of sound waves that interact inside a closed duct (a resonant cavity) showed the formation of linear and nonlinear standing waves, depending on the amplitude of the sound waves. The analysis of the interaction of two sound waves with opposing phases showed that, as the intensity of the sound increases, the efficacy of the noise cancellation is reduced. Moreover, the simulation of the continuous interaction of sound waves inside the cavity showed that for high amplitudes, the system eventually reaches an equilibrium between the energy input from the generation of the sound waves and the energy loss caused by the shock waves formed due to the nonlinear effects, and the pressure fluctuations remain approximately constant. It was possible to simulate the nonlinear sound waves and the results agree with the theory of nonlinear acoustics.
Keywords
Computational aeroacoustics, Nonlinear acoustics, Acoustic resonators, Immersed Boundary Method, Inviscid flow
