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Simulation of magnetic positive positioning of propellants (MP 3 ) in full-scale applications depends on the ability to model the shape and strength of the magnetic fields required to induce fluid flow. A previous effort to integrate an electromagnetic field and incompressible fluid flow model yielded a unique tool that can be used to predict fluid motion induced by a magnetic field. The enhanced computational simulation is used to predict an optimal configuration for an upcoming flight experiment focused on studying the influence of a magnetic field on LOX in reduced gravity. Simulations of magnetic positive positioning of LOX are presented and the influence of the magnetic field and background acceleration on the settling time is investigated to determine an appropriate tank and liquid configuration to induce successful reorientation during the flight experiment. Variations in the magnet thickness, LOX tank size, background acceleration, and LOX tank fill are considered to predict the optimal experiment design. The magnetic Bond number and a dimensionless reorientation time are utilized as correlating parameters for this study and may be useful in future efforts to relate magnetically induced flows for small-scale experiments to the behavior of propellants in full-size systems.

(Abridged) Most massive protostars exhibit bipolar outflows. Nonetheless, there is no consensus regarding the mechanism at the origin of these outflows, nor on the cause of the less-frequently observed monopolar outflows. We aim to identify the origin of early massive protostellar outflows, focusing on the combined effects of radiative transfer and magnetic fields in a turbulent medium. We use four state-of-the-art radiation-magnetohydrodynamical simulations following the collapse of massive 100 Msun pre-stellar cores with the Ramses code. Turbulence is taken into account via initial velocity dispersion. We use a hybrid radiative transfer method and include ambipolar diffusion. We find that turbulence delays the launching of outflows, which appear to be mainly driven by magnetohydrodynamical processes. Magnetic tower flow and the magneto-centrifugal acceleration contribute to the acceleration and the former operates on larger volumes than the latter. Our finest resolution, 5 AU, does not allow us to get converged results on magneto-centrifugally accelerated outflows. Radiative acceleration takes place as well, dominates in the star vicinity, enlarges the outflow extent, and has no negative impact on the launching of magnetic outflows (up to M~17 Msun, L~1e5 Lsun). The associated opening angles (20-30 deg when magnetic fields dominate) suggest additional (de-)collimating effects to meet observational constraints. Outflows are launched nearly perpendicular to the disk and are misaligned with the initial core-scale magnetic fields, in agreement with several observational studies. In the most turbulent run, the outflow is monopolar. We conclude that magnetic processes dominate the acceleration of massive protostellar outflows up to ~17 Msun, against radiative processes. Turbulence perturbs the outflow launching and is a possible explanation for monopolar outflows., Accepted for publication in A&A, 20 pages, 15 figures

International audience; In this paper, we study longitudinal motion controlof car-like vehicles platoon navigating in an urban environmentwith minimum communication links. To achieve a higher trafficflow, a constant-spacing policy between successive vehicles iscommonly used but this is at a cost of an increased number ofcommunication links as any vehicle information must broadcastto all its followers. Therefore, we propose a distributed observer-based control law that depends both on communicated andmeasured information. Our formulation allows designing thecontrol law directly in the curvilinear coordinates. Internal andstring stability analysis are conducted. We provide simulationresults, through dynamic vehicular mobility simulator, to illus-trate the feasibility of the proposed approach and corroborate our theoretical findings.