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

Collision-Free Rendezvous Maneuvers for Formations of Unmanned Aerial Vehicles

This article discusses the rendezvous maneuver for a fleet of small fixed-wing Unmanned Aerial Vehicles (UAVs). Trajectories have to be generated on-line while avoiding collision with static and dynamic obstacles and minimizing rendezvous time. An approach based on Model Predictive Control (MPC) is investigated which assures that the dynamic constraints of the UAVs are satisfied at every time step. By introducing binary variables, a Mixed Integer Linear Programming (MILP) problem is formulated. Computation time is limited by incorporating the receding horizon technique. A shorter planning horizon strongly reduces computation time, but delays detection of obstacles which can lead to an infeasible path. The result is a robust path planning algorithm that satisfies the imposed constraints. However, further relaxation of the constraints and fine-tuning is necessary to limit complexity

COOLFluiD v2.0.0

This code version includes the core COOLFluiD framework and numerical solvers for flows and plasmas on unstructured meshes. In particular, this version includes a bunch of new features which have been developed within the last year (2016/2017): support for static linking (it was broken before), (GPU-enabled) ion-electron and ion-neutral multi-fluid plasma model, flux reconstruction method, finite volume-based radiation algorithm, interface to PARALUTION for solving linear systems on GPU

Artificial Gravity Conceptual Orbiting Station Design

One of the key challenges of long term human presence for exploration and research in low earth orbit is the microgravity environment. This environment is a key enabler for research on today’s International Space Station (ISS), but is also a major factor contributing to negative effects on the human body and mind. In order to expand the capabilities of a future orbiting station the element of artificial gravity will need to be added. During the summer of 2016 a team of space professionals looked into the design challenges of a large orbiting facility in low Earth orbit. This design challenge was part of the Space Studies Program 2016 of the International Space University, hosted at the Technion Israel Institute of Technology in Haifa. This orbiting facility should not only support microgravity and other space-based research, but also be a place to live, work and visit for much larger numbers of people than current space stations. The Artificial Gravity Conceptual Vehicle Design includes key engineering and design considerations for a crewed low Earth orbit space station, which uses rotation to provide artificial gravity. It will have a center section which will provide a microgravity environment for research and manufacturing, and will also serve as the docking location for the station. This vehicle will be a grand complex. It is designed to be orbited in the 2035 to 2040 timeframe, and it will make living and working in space commonplace. The station will be very large and provide an environment compatible with work and tourism. It is expected that up to 200 people may reside on the complex at any one time. Workers and their families will live onboard. A hotel to house tourists will be part of the complex. There will be schools, stores, green areas with ponds or streams, a cinema, restaurants, etc