scholarly journals The Technique of MIEELDLD in Computational Aeroacoustics

2012 ◽  
Vol 2012 ◽  
pp. 1-30
Author(s):  
A. R. Appadu
Keyword(s):  
Fluid Dynamics ◽  
High Order ◽  
Computational Aeroacoustics ◽  
Advection Equation ◽  
Optimal Parameters ◽  
Numerical Schemes ◽  
Low Dissipation ◽  
Linear Advection Equation ◽  
Discretization Schemes ◽  
Low Dispersion

The numerical simulation of aeroacoustic phenomena requires high-order accurate numerical schemes with low dispersion and low dissipation errors. A technique has recently been devised in a Computational Fluid Dynamics framework which enables optimal parameters to be chosen so as to better control the grade and balance of dispersion and dissipation in numerical schemes (Appadu and Dauhoo, 2011; Appadu, 2012a; Appadu, 2012b; Appadu, 2012c). This technique has been baptised as the Minimized Integrated Exponential Error for Low Dispersion and Low Dissipation (MIEELDLD) and has successfully been applied to numerical schemes discretising the 1-D, 2-D, and 3-D advection equations. In this paper, we extend the technique of MIEELDLD to the field of computational aeroacoustics and have been able to construct high-order methods with Low Dispersion and Low Dissipation properties which approximate the 1-D linear advection equation. Modifications to the spatial discretization schemes designed by Tam and Webb (1993), Lockard et al. (1995), Zingg et al. (1996), Zhuang and Chen (2002), and Bogey and Bailly (2004) have been obtained, and also a modification to the temporal scheme developed by Tam et al. (1993) has been obtained. These novel methods obtained using MIEELDLD have in general better dispersive properties as compared to the existing optimised methods.

High-Order Optimized Numerical Schemes for Computational Aeroacoustics

2001 ◽  
Author(s):  
S. Zheng ◽  
M. Zhuang
Keyword(s):  
Finite Difference ◽  
Sound Field ◽  
High Order ◽  
Finite Difference Schemes ◽  
Computational Aeroacoustics ◽  
Optimization Approach ◽  
Numerical Schemes ◽  
Broadband Waves ◽  
High Order Finite Difference ◽  
Better Than

Abstract This paper presents a new optimization approach for the high-order finite difference schemes. Due to the fact that it is common for a sound field to consist of several dominant wavenumbers, the proposed numerical schemes are optimized at these dominant wavenumbers instead of over a range of wavenumber. These optimized multi-component schemes, as referred to in this paper, give very accurate solutions if used to predict an acoustic wave traveling with these dominant wavenumbers. In addition, for broadband waves, it is shown that the performance of the optimized upwind multi-component scheme is comparable to that of the optimized upwind broadband scheme, which is optimized over a range of wavenumber. The results of the Fourier analysis also show that the optimized central multi-component schemes are at least comparable to if not better than the optimized central broadband schemes when solving broadband waves.

High-order low-dissipation low-dispersion diagonally implicit Runge–Kutta schemes

2015 ◽  
Vol 286 ◽  
pp. 38-48 ◽  
Author(s):  
Farshid Nazari ◽  
Abdolmajid Mohammadian ◽  
Martin Charron
Keyword(s):  
High Order ◽  
Low Dissipation ◽  
Runge Kutta ◽  
Low Dispersion

High order boundary treatment for high order methods in computational fluid dynamics

2016 ◽  
Author(s):  
André Ribeiro de Barros Aguiar ◽  
Carlos Breviglieri ◽  
Fábio Mallaco Moreira ◽  
Eduardo Jourdan ◽  
João Luiz F. Azevedo
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
High Order ◽  
High Order Methods ◽  
Boundary Treatment

scholarly journals Detailed Modeling of Cork-Phenolic Ablators in Preparation for the Post-flight Analysis of the QARMAN Re-entry CubeSat

2021 ◽  
Author(s):  
Claudio Miccoli ◽  
Alessandro Turchi ◽  
Pierre Schrooyen ◽  
Domenic D’Ambrosio ◽  
Thierry Magin
Keyword(s):  
Fluid Dynamics ◽  
Thermal Protection ◽  
A Priori ◽  
European Space Agency ◽  
Thermal Response ◽  
Accurate Method ◽  
Navier Stokes ◽  
Advection Equation ◽  
High Enthalpy ◽  
Space Agency

AbstractThis work deals with the analysis of the cork P50, an ablative thermal protection material (TPM) used for the heat shield of the qarman Re-entry CubeSat. Developed for the European Space Agency (ESA) at the von Karman Institute (VKI) for Fluid Dynamics, qarman is a scientific demonstrator for Aerothermodynamic Research. The ability to model and predict the atypical behavior of the new cork-based materials is considered a critical research topic. Therefore, this work is motivated by the need to develop a numerical model able to respond to this demand, in preparation to the post-flight analysis of qarman. This study is focused on the main thermal response phenomena of the cork P50: pyrolysis and swelling. Pyrolysis was analyzed by means of the multi-physics Computational Fluid Dynamics (CFD) code argo, developed at Cenaero. Based on a unified flow-material solver, the Volume Averaged Navier–Stokes (VANS) equations were numerically solved to describe the interaction between a multi-species high enthalpy flow and a reactive porous medium, by means of a high-order Discontinuous Galerkin Method (DGM). Specifically, an accurate method to compute the pyrolysis production rate was implemented. The modeling of swelling was the most ambitious task, requiring the development of a physical model accounting for this phenomenon, for the purpose of a future implementation within argo. A 1D model was proposed, mainly based on an a priori assumption on the swelling velocity and the resolution of a nonlinear advection equation, by means of a Finite Difference Method (FDM). Once developed, the model was successfully tested through a matlab code, showing that the approach is promising and thus opening the way to further developments.

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