Implicit High-Order Flux Reconstruction Solver for High-Speed Compressible Flows

The present paper addresses the development and implementation of the first high-order Flux Reconstruction (FR) solver for high-speed flows within the open-source COOLFluiD (Computational Object-Oriented Libraries for Fluid Dynamics) platform. The resulting solver is fully implicit and able to simulate compressible flow problems governed by either the Euler or the Navier-Stokes equations in two and three dimensions. Furthermore, it can run in parallel on multiple CPU-cores and is designed to handle unstructured grids consisting of both straight and curved edged quadrilateral or hexahedral elements. While most of the implementation relies on state-of-the-art FR algorithms, an improved and more case-independent shock capturing scheme has been developed in order to tackle the first viscous hypersonic simulations using the FR method. Extensive verification of the FR solver has been performed through the use of reproducible benchmark test cases with flow speeds ranging from subsonic to hypersonic, up to Mach 17.6. The obtained results have been favorably compared to those available in literature. Furthermore, so-called super-accuracy is retrieved for certain cases when solving the Euler equations. The strengths of the FR solver in terms of computational accuracy per degree of freedom are also illustrated. Finally, the influence of the characterizing parameters of the FR method as well as the the influence of the novel shock capturing scheme on the accuracy of the developed solver is discussed

Effect of electron number densities on the radio signal propagation in an inductively coupled plasma facility

Spacecraft entering a planetary atmosphere are surrounded by a plasma layer containing high levels of ionization, due to the extreme temperatures in the shock layer. The high electron number densities cause attenuation of the electromagnetic waves emitted by the on-board antennas, leading to communication blackout for several minutes. This work presents experimental measurements of signal propagation through an ionized plasma flow. The measurements are conducted at the VKI plasma wind tunnel (Plasmatron) using conical horn antennas transmitting in the Ka-band, between 33 and 40 GHz. Testing conditions at 15, 50 and 100 mbar, and powers between 100 and 600 kW cover a broad range of the testing envelope of the Plasmatron as well as a broad range of atmospheric entry conditions. The transmitting antenna is characterized at the UPC anechoic chamber, obtaining the radiation patterns, beamwidth, and gain at the boresight direction; and an optical ray tracing technique is used to describe the electromagnetic waves propagation in the plasma flowfield inside of the Plasmatron chamber. The signal propagation measurements show clear attenuation when the signal is propagating through the plasma, varying between 2 and 15 dB depending on the testing conditions. This attenuation increases with electron number densities, which are driven by the Plasmatron power and pressure settings. Preliminary evidence of Faraday rotation effects caused by the plasma is also observed.Diana Luís research is funded by a doctoral fellowship (2021.04930.BD) granted by Fundação para a Ciência e Tecnologia (FCT Portugal). The research of Vincent Fitzgerald Giangaspero is supported by SB PhD fellowship 1SA8219N of the Research Foundation - Flanders (FWO). The resources and services used for the BORAT simulations were provided by the VSC (Flemish Supercomputer Center), funded by the Research Foundation - Flanders (FWO) and the Flemish Government. The MEESST project is funded by the European Union’s Horizon 2020 research and innovation programme under grant agreement No 899298.Peer ReviewedPostprint (published version

Modeling and Simulation of Radiative Compressible Flows in Aerodynamic Heating Arc-Jet Facility

Numerical simulations of an arc heated flow inside NASA's 20 [MW] Aerodynamics heating facility (AHF) are performed in order to investigate the three-dimensional swirling flow and the current distribution inside the wind tunnel. The plasma is considered in Local Thermodynamics Equilibrium(LTE) and is composed of Air-Argon gas mixture. The governing equations are the Navier-Stokes equations that include source terms corresponding to Joule heating and radiative cooling. The former is obtained by solving an electric potential equation, while the latter is calculated using an innovative massively parallel ray-tracing algorithm. The fully coupled system is closed by the thermodynamics relations and transport properties which are obtained from Chapman-Enskog method. A novel strategy was developed in order to enable the flow solver and the radiation calculation to be preformed independently and simultaneously using a different number of processors. Drastic reduction in the computational cost was achieved using this strategy. Details on the numerical methods used for space discretization, time integration and ray-tracing algorithm will be presented. The effect of the radiative cooling on the dynamics of the flow will be investigated. The complete set of equations were implemented within the COOLFluiD Framework. Fig. 1 shows the geometry of the Anode and part of the constrictor of the Aerodynamics heating facility (AHF). Fig. 2 shows the velocity field distribution along (x-y) plane and the streamline in (z-y) plane

3D Ray Tracing Solver for Communication Blackout Analysis in Atmospheric Entry Missions

During the atmospheric entry phase at hypersonic speed, the radio communication from/to a space vehicle can be disrupted due to the formation of a plasma sheath within the surrounding flow field. In order to characterize such communication blackout phases, this work presents a numerical methodology combining Computational Fluid Dynamic (CFD) simulations of ionized chemically reacting entry flows by means of Computational Object-Oriented Libraries for Fluid Dynamics (COOLFluiD) and a ray tracing analysis by means of the newly developed BlackOut RAy Tracer (BORAT). The latter is based on the numerical solution of the 3D Eikonal system of equations, offering a fast, efficient and accurate method to analyse the interaction between electromagnetic signals and weakly ionised plasmas. The proposed methodology, and BORAT in particular, is first verified on popular benchmark cases and then used to analyse the European Space Agency (ESA) 2016 ExoMars Schiaparelli entry flight into Martian environment. The corresponding results demonstrate the validity of the proposed ray tracing approach for predicting communication blackout, where signals emitted from the on-board antenna undergo reflection and refraction from the plasma surrounding the entry vehicle, and the advantage of a 3D approach for analysing real flight configuration

Magnetohydrodynamic Enhanced Entry System for Space Transportation (MEESST) as a Key Building Block for Future Exploration Missions

Aside from the launch environment, atmospheric re-entry imposes one of the most demanding environments which a spacecraft can experience. The combination of high spacecraft velocity and the presence of atmospheric particles leads to partially ionised gas forming around the vehicle, which significantly inhibits radio communications, and leads to the generation of high thermal loads on the spacecraft surface. Currently, the latter is solved using expensive, heavy, and often expendable thermal protection systems (TPS). The use of electromagnetic fields to exploit Magnetohydrodynamic (MHD) principles has long been considered as an attractive solution for this problem. By displacing the ionised gas away from the spacecraft, the thermal loads can be reduced, while also opening a magnetic window for radio waves, mitigating the blackout phenomenon. The application of this concept has to date not been possible due to the large magnetic fields required, which would necessitate the use of exceptionally massive and power-hungry copper coils. High Temperature Superconductors (HTS) have now reached industrial maturity. HTS coils can now offer the necessary low weight and compactness required for space applications. The MEESST consortium the has been awarded a grant from the EU Horizon 2020 programme for the development and demonstration of a novel HTS-based re-entry system based with its foundation on MHD principles. The project will first harmonize existing numerical codes, and then design, manufacture, and test a HTS magnet. The study shows that the use of MEESST technology can have a positive impact on the cost-effectiveness and available payload of interplanetary missions

National framework for inclusion

Inclusive education is the cornerstone of Scottish education and, as such, must be of the highest priority for the Scottish Government and for all those involved in education in Scotland. There is clear recognition of the fact that teachers need to be well prepared and appropriately supported throughout their careers if they are to succeed in developing and sustaining the desired inclusive practice which will enable them to meet the increasingly diverse needs of all children within schools in Scotland