Fan noise is one of the leading source of aircraft noise. The CleanSky European project is aimed at developing environmentally friendly airplanes, which would burn less fuel and also emit less noise. As part of the Smart Fixed Wing Aircraft, one of the six platforms of the CleanSky project, Dassault Aviation is working on the integration of aft-body concept for engine noise shielding [1]. An innovative U-tail aircraft model equipped with turbine powered simulators was wind-tunnel tested to assess the acoustic shielding effect of the U-tail on a typical business jet with side-mounted engines. As part of the modeling of the noise shielding effect, the acoustic propagation of a known mode in the jet engine to the surrounding space has to be computed. As the flow of the engine considerably changes the way the acoustic waves propagate, pure Helmholtz equations are not sufficient. Linearized Euler or Navier-Stokes equations are needed to take into account the acoustic refraction induced by the mean flow. Aether is a finite element solver on unstructured meshes for the compressible Navier-Stokes equations, stabilised using the supg method. It was fully developed in-house at Dassault Aviation. It was linearized for aeroelasticity applications [2], and shape optimisation [3]. For aeroacoustics, the high-order capability of Aether was kept [4]. Figure 1: Plane mode at 2000Hz with no base flow. Left: real part of the pressure variation in Pa. Right: comparison of directivities between linearized Navier-Stokes and a BEM method (SPECTRE) For validation purpose, computations were done without mean flow, and the results were compared

To create efficient new aerodynamic designs or predict the onset of flutter, the linearised Navier-Stokes equations might be used. In some cases, many right-hand sides must be solved keeping the same matrix. In this paper, techniques which enable to solve several righthand sides at the same time, such as Block GMRes, or reuse pieces of information computed in the previous solves, such as Krylov space recycling, are investigated. They will be tested on both simple and industrial test cases.

This chapter describes Dassault Aviation's contribution to Workpackage 5 of the ADIGMA Project. The adjoint operator developed in the framework of optimum design is used to estimate the error in the solution with respect to a given target quantity. Local values of this error estimation are used as a criterion to refine the mesh. This yields significant improvement over traditional criteria based on the residual or on gradients of physical quantities. The method is carefully tested using inviscid, transonic, laminar, and high Reynolds number turbulent flows.

This chapter covers Dassault Aviation's contribution to Workpackage 3 of the ADIGMA Project, which focuses on the extension of its stabilized finite element industrial Navier-Stokes code to higher-order elements. Mesh generation aspects are treated and especially the issue of highly-stretched curved elements close to the wall boundary of Navier-Stokes meshes. The high-order approach is carefully assessed using inviscid subsonic and transonic, laminar, and high Reynolds number turbulent flows.

Efficient and reliable simulation-based processes are essential to the design of innovative and competitive future aircraft. Continued efforts over the past years have lead to impressive progress and new tools. The review presentation will illustrate key issues associated to the following topics: automatic shape optimization, aerodynamic models for aeroelastic analysis, Detached Eddy Simulation (DES) for complex flows and loads, aeroacoustics and uncertainty quantification.

The paper first describes developments performed to achieve an accurate and efficient simulation capacity using turbulence models based on the LES and DES approaches. The development is performed within the industrial code used at Dassault for the aerodynamics design of both military aircraft and business jets. The issues of subgrid scale implementation and wall treatment approaches are addressed. The paper then presents industrial applications performed at Dassault related to aerodynamic design. Examples demonstrate the impact of LES and DES on key design issues where complex flow features are present.

This paper presents validation test cases of an LES solver based on an unstructured finite-element compressible Navier-Stokes code. After a short description of the industrial tool, we explain the incremental approach we have adopted in order to attain a reliable LES capability. Each step is illustrated by numerical examples and comparisons with experiments or theoretical results.

An integrated scramjet experiment is proposed as an Integration Validation Object. A model was tested in different facilities at ITAM with and without combustion. The behavior of the three-dimensional inlet was experimentally studied in great detail. As a first step in the validation process, we present the numerical reconstruction of the flow past the inlet at a Mach number of 6.