Corentin Carton de Wiart

Assessment of a High-Order Discontinuous Galerkin Method for the Direct Numerical Simulation of Transition at Low-Reynolds Number in the T106C High-Lift Low Pressure Turbine Cascade

An implicit time integration, high-order discontinuous Galerkin method is assessed on the DNS of the flow in the T106C cascade at low Reynolds number. This code, aimed at providing high orders of accuracy on unstructured meshes for DNS and LES simulations on industrial geometries, was previously successfully assessed on fundamental, academic test cases. The computational results are compared to the experimental values and literature, and the obtained flow field characteristics are discussed. Although adequate resolution is supposed to be attained, discrepancies with respect to the experiment are found. These differences were furthermore consistently found by all authors in the workshop on high-order methods for CFD. The origins are therefore conjectured to result from insufficient adequation between computational setup and experiments, as no modeling is assumed. A plan for further investigation is proposed.Copyright

Application of wall-models to discontinuous Galerkin LES

Wall-resolved Large-Eddy Simulations (LES) are still limited to moderate Reynolds number flows due to the high computational cost required to capture the inner part of the boundary layer. Wall-modeled LES (WMLES) provide more affordable LES by modeling the near-wall layer. Wall function-based WMLES solve LES equations up to the wall, where the coarse mesh resolution essentially renders the calculation under-resolved. This makes the accuracy of WMLES very sensitive to the behavior of the numerical method. Therefore, best practice rules regarding the use and implementation of WMLES cannot be directly transferred from one methodology to another regardless of the type of discretization approach. Whilst numerous studies present guidelines on the use of WMLES, there is a lack of knowledge for discontinuous finite-element-like high-order methods. Incidentally, these methods are increasingly used on the account of their high accuracy on unstructured meshes and their strong computational efficiency. The present pa...

Development of a Discontinuous Galerkin Solver for High Quality Wall-Resolved/Modelled DNS and LES of Practical Turbomachinery Flows on Fully Unstructured Meshes

The development of a high-order CFD solver for LES of turbomachinery is discussed. It is integrated in a flexible multiphysics platform Argo based on the discontinuous Galerkin Method. The DGM bridges the gap between the flexibility of the industrial solvers and the accuracy of the academic methods, as it is able to reach high order of accuracy on fully unstructured and hybrid meshes. Due to its inherent data locality, it also features high serial and parallel efficiency. The method provides a natural framework for adaptation of mesh size and interpolation order, which can be used later to further reduce computational cost and at the same time increase reliability of industrial DNS and LES. The paper mainly focuses on the physical modelling aspects and their interaction with the discretisation. In particular implicit LES and wall modelling is discussed. The approaches are tested on the wall-resolved and modelled LES of the turbulent channel flow. Finally the approach is applied to resolved LES of the near-transonic transitional flows in a low-pressure turbine cascade at Re = 9.4 × 104 and a compressor cascade at Re = 6.0 × 105. Either cases feature the full span and include end wall effects.Copyright

Design of a Modular Monolithic Implicit Solver for Multi-Physics Applications

The design of a modular multi-physics high-order space-time finite-element framework is presented together with its extension to allow monolithic coupling of different physics. One of the main objectives of the framework is to perform efficient high-fidelity simulations of capsule/parachute systems. This problem requires simulating multiple physics including, but not limited to, the compressible Navier-Stokes equations, the dynamics of a moving body with mesh deformations and adaptation, the linear shell equations, non-reflective boundary conditions and wall modeling. The solver is based on high-order space-time finite element methods. Continuous, discontinuous and C-discontinuous Galerkin methods are implemented, allowing one to discretize various physical models. Tangent and adjoint sensitivity analysis are also targeted in order to conduct gradient-based optimization, error estimation, mesh adaptation, and flow control, adding another layer of complexity to the framework. The decisions made to tackle these challenges are presented. The discussion focuses first on the “single-physics” solver and later on its extension to the monolithic coupling of different physics. The implementation of different physics modules, relevant to the capsule/parachute system, are also presented. Finally, examples of coupled computations are presented, paving the way to the simulation of the full capsule/parachute system.

A discontinuous Galerkin method for implicit LES of moderate Reynolds number ows

ow. Several Reynolds number (up to Re = 950) are studied. The results show a fair agreement with the reference DNS, showing the ability of the method to perform accurate ILES on regular grids. Then, the method is applied on several advanced benchmarks (studied in the European project IDIHOM), performed at moderate Reynolds number. The 2D periodic hill ow, the low pressure turbine blade T106C and the JEAN nozzle benchmarks are considered. Encouraging results have been obtained, paving the way to the use of the method for industrial applications.

The Discontinuous Galerkin Method as an Enabling Technology for DNS and LES of Industrial Aeronautical Applications

To enhance prediction capacities and therefore allow more advanced aeronautic and aero-propulsive design, new CFD tools are required. State of the art codes are based on second order accurate finite volume methods and are primarily developed for statistical turbulence modeling approaches. Given the limitations of these models, more direct approaches such as DNS or LES are required for the prediction of off-design aerodynamic performance, noise generation, transitional flows ...