Search

International audience; Some possible future High Fidelity CFD codes for LES simulation of turbomachinery are compared on several test cases increasing in complexity , starting from a very simple inviscid Vortex Convection to a multistage axial experimental compressor. Simulations were performed between 2013 and 2016 b y major Safran partners (Cenaero, Cerfacs, CORIA and Onera) and various numerical methods compared : Finite Volume, Discontinuous Galerkin, Spectral Differences. Comparison to analytical results, to experimental data or to RANS simulations are performed to check and measure accuracy. CPU efficiency versus accuracy are also presented. It clearly appears that the level of maturity could be different between codes and numerical approaches. In the end, advantages and disadvantages of every codes obtained during this project are presented.

In this article, the results of aeroacoustic cases obtained by high-order methods are presented. One internal and one external case are considered. The internal case is a transonic cavity. It has been computed by three parters, namely FOI-LiU (Linkoping University), University of Stuttgart (USTUTT) and Dassault Aviation (DASSAV). FOI-LiU has computed with their higher order accurate finite difference solver using a block structured grid. Comparisons are made to reference calculations using an unstructured grid with Edge. USTUTT uses a high order discontinuous Galerkin spectral element code for the final high-order computations and a mixed modal/nodal DG code for the baseline computations. Dassault Aviation uses their in-house stabilized finite element code Aether, both for the reference and the higher-order computations. In both instances unstructured tetrehedral grids are used. The external case is a quasi-two dimensional generic wing and flap configuration defined in the VALIANT FP7 project. Two institutions were involved in the high-order simulation of this low-Mach number test case, M = 0.15, Central Institute of Aero- and Hydrodynamics, TsAGI, and the von Karman Institute, VKI. In the following, the acoustic predictions corresponding to the two test cases will be described.

The paper investigates a new methodology to rebuild freestream conditions for the trajectory of a reentry vehicle from stagnation-point measurements. Uncertainties due to measurements and model parameters are taken into account, and a Bayesian setting supplied with metamodels is used to solve the associated stochastic inverse problem. A sensitivity analysis based on a stochastic spectral framework is first investigated to study the impact of uncertain input data on stagnation-point measurements. An original backward uncertainty propagation method is then proposed, for which only the uncertainties that have the most impact are retained.

The post§ight analysis of a space mission requires accurate determination of the free-stream conditions for the trajectory. The Mach number, temperature, and pressure conditions can be rebuilt from the heat §ux and pressure measured on the spacecraft by means of a Flush Air Data System (FADS). This instrumentation comprises a set of sensors §ush mounted in the thermal protection system to measure the static pressure (pressure taps) and heat §ux (calorimeters). Knowing that ex

The paper investigates a new methodology to rebuild freestream conditions for the trajectory of a re-entry vehicle from measurements of stagnation-point pressure and heat flux. Uncertainties due to measurements and model parameters are taken into account and a Bayesian setting is used to solve the associated stochastic inverse problem. A sensitivity analysis based on a stochastic spectral framework is first investigated to study the impact of uncertain input data on stagnation-point measurements. An original backward uncertainty propagation method is then proposed, for which only the uncertainties that have the most impact are retained.

International audience; This article deals with the latest development in the construction of monotone high-order residual distribution schemes (RDS) on quadrilateral meshes. In the first part we give some generalities about the way upwind high-order RDS is designed. In the second part, some standard schemes are described. Then, the design of a stabilization to help the convergence is shown. The last part of this article is dedicated to the results obtained with these schemes.

The COOLFluiD (Computational Object Oriented Libraries for Fluid Dynamics) project, officially started in 2002, has lead to the creation of a world-class, extremely modular collaborative platform for high-performance scientific computing and multi-physics modeling. Target applications include Space Weather modeling, aeroacoustics, turbulence, aerothermodynamics for aerospace problems ranging from incompressible regime to hypersonics, steady and unsteady flows, etc. COOLFluiD features a unique collection of parallel numerical solvers for unstructured meshes, where each physical model (set of PDE’s, variable transformation, aerothermochemical properties, etc.) or numerical algorithm (space discretization, time discretization, coupling strategy, linear system solver interface, etc.) is enclosed in a separate module which is loaded dynamically at run-time. The paper presents a concise description about the main design strengths of the platform, an overview of current capabilities (in terms of numerical methods and physical models) and a gallery of the most challenging applications tackled so far. Particular attention is devoted to the computational modeling of aerothermodynamics and plasma flows, including atmospheric re-entry flows and numerical simulation of experiments in high-enthalpy facilities.