Hydrogen release from a high-pressure chamber is modeled in this paper. Two approaches are developed to investigate the real gas effects at high pressures. In the first method, an analytical model is developed to simulate time histories of stagnation properties of hydrogen inside the chamber as well as sonic properties of hydrogen at the orifice. Corresponding thermodynamic relations, which describe the specific heats, internal energy, and speed of sound, are derived based on the Beattie-Bridgeman state equation. In the second approach, a 3-D unstructured tetrahedral finite volume Euler solver is applied to numerically simulate the hydrogen release. The solver is modified to take into account the real gas effects. Modifications required to calculate the real gas Jacobian matrices and eigenvectors as well as to obtain the Roe's averaged convective fluxes are described. Real gas effect is modeled by the same state equation. Numerical and analytical results are compared for ideal and real gas conditions. An excellent agreement is reported.

The behavior of the tip-vortex behind a square NACA0015 wing was numerically investigated. The problems studied include the stationary and the oscillating wing at static and dynamic stall conditions. Reynolds-averaged Navier-Stokes (RANS) and detached-eddy simulation (DES) schemes were implemented. Vortex structures predicted by RANS were mainly diffused while DES was able to produce qualitatively and quantitatively better results as compared to the experimental data. The break-up of the tip vortex, which started at the end of the upstroke and continued to the middle of the downstroke over an oscillation cycle, was observed in DES data.

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A mesh movement algorithm suitable for aerodynamic design optimization problems is presented. It involves B-spline surface construction, projection and evaluation on B-spline faces for the surface mesh movement, as well as inverse-distance and 2D/3D TFI interpolations for the volume mesh deformation. The algorithm is fast and exhibits an excellent parallel efficiency. It is used to deform the surface and volume mesh of an ONERA-M6 wing undergoing several planform changes. The quality of the deformed mesh is preserved as long as the difference between the initial surface mesh and the B-spline surface model is small. A good agreement reported between the flow simulation results on the deformed mesh and those obtained on initial fixed mesh.

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