A. Munafo and K. Benssasi successfully defended their theses

Alessandro Munafo has successfully defended his doctoral thesis at Ecole Centrale Paris on 2^1st January 2014. His thesis work was entitled "Multi-scale models and computational methods for aerothermodynamics applications."

The research on multi-scale models has focused on internal energy excitation and dissociation of molecular gases in atmospheric entry flows. The scope was two-fold: to gain insight into the dynamics of internal energy excitation and dissociation in the hydrodynamic regime and to develop reduced models for Computational Fluid Dynamics applications. The reduced models have been constructed by coarsening the resolution of a detailed rovibrational collisional model developed based on ab-initio data for the N2-N system provided by the Computational Quantum Chemistry Group at NASA Ames Research Center. Different mechanism reduction techniques have been proposed. Their application led to the formulation of conventional macroscopic multi-temperature models and vibrational collisional models, and innovative energy bin models. The accuracy of the reduced models has been assessed by means of a systematic comparison with the predictions of the detailed rovibrational collisional model. Ap  plications considered are inviscid flows behind normal shock waves, within converging-diverging nozzles and around axisym- metric bodies, and viscous flows along the stagnation-line of blunt bodies.

The research on computational methods has focused on rarefied flows. The scope was to formulate a deterministic numerical method for solving the Boltzmann equation in the case of multi-component gases with internal energy by accounting for both elastic and inelastic collisions. The numerical method is based on the weighted convolution structure of the Fourier transformed Boltzmann equation. Applications considered are the time-evolution of an isochoric gaseous system initially set in a non-equilibrium state and the steady flow across a normal shock wave. The accuracy of the proposed numerical method has been assessed by comparing the moments extracted from the velocity distribution function with Direct Simulation Monte Carlo (DSMC) method predictions."

Khalil Bensassi successfully defended his doctoral thesis on “Numerical Modeling of the VKI Longshot Hypersonic Wind Tunnel” at Ecole Polytechnique de Bruxelles in January 2014.

The development of future space vehicle requires hypersonic ground testing and extensive computations before the real flight. The success of a mission will depend on the reliability of the experimental data, the accuracy of the CFD and the methodology used to extrapolate these data from ground test to flight.  The increase of the computational resources, the recent development in physical modelling and numerical schemes have given the computational part much more important role in the space missions. The validation of the computational codes with experimental data is more than necessary, thus, accurate ground test conditions are needed.
The free stream conditions in most hypersonic wind tunnel are very difficult to assess and remain one of the most challenging task, even in the recent hypersonic facility.  The uncertainties on their values could reach up to  20%. It is  mostly due to a lack of experimental data on some part of the facility like inside the nozzle or in driven-driven tubes and also to some technical difficulties to measure some main flow parameters. The usual method to overcome this limitation is to rebuild those missing data using one dimensional solver based on isentropic assumptions. Moreover the  current multidimensional numerical simulations concern only some part of the facility like the nozzle or the driven which is far from being enough for a good understanding of the facility.  In order to investigate the flow field in the VKI-Longshot facility, numerical computations of the flow in the driver-driven tubes and the hypersonic nozzle nozzle were performed.

Inauguration of two facilities at VKI

In the presence of the State Minister Philippe Courard, the VKI and the SCK•CEN inaugurate this morning two unique facilities: a sloshing table reproducing the seismic activity (Shakespeare) and a water model (MYRRHABelle) of the research infrastructure Myrrha.

Myrrha is a multifunctional research infrastructure developed by "le Centre d’Etude de l’Energie Nucléaire" (SCK•CEN). Myrrha is the innovative and unique high energy accelerator and Lead-Bismuth-Eutectic cooled reactor project, initiated by the SCK•CEN of Mol, and supported by BELSPO.

QB50 launch contract signed

The von Karman Institute from Sint Genesius Rode (Belgium ) and the Alcantara Cyclone Space from Brasilia (Brazil) signed on Monday 27 January, 2014 the launcher contract for the QB50 project co-funded by the European Commission’s Framework Program 7.

Free download: Review of the VKI Doctoral Research

COPA-GT Fellows at VKI

16 young Fellows involved in the European project on "Coupled Parallel Simulation of Gas Turbines" (COPA-GT) are here at VKI from 13 to 17 January 2014 to follow courses in the field of propulsion.