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Vortical Solutions in Supersonic Corner Flows
No full textVortical solutions are investigated for inviscid supersonic steady flows,described by the steady-state Euler equations, that occur in the corner region generated by two orthogonal ramps. Complex shock interactions appear, with the formationof a vorticity field in t h ecornerregion and the vorticity itself converging into spiral singularities. Symmetric or asymmetric flow configurations are generated within symmetric corners. The Investigation iscarried out by anumerical technique based on aspace-marching procedurewith afinite volume approximation. The integration of the conservation laws allows for the correct numerical capturing of shocks and contact surfaces. A flux-difference-splitting procedure i sused for the calculation of the fluxes on the side wallsof the volumes, based on the hyperbolicity of the Euler equations for steady supersonic regimes. A high-order accuracy scheme is introduced foundedon the essentially nonoscillatory(ENO) scheme. Numerical results are presented anddiscussed with reference to similar problems investigated by other author
A Computational Method for Combustion in High Speed Flows
Full text linkA two-dimensional time-accurate numerical model to simulate complex reacting flowfields in chemical non-equilibrium is presented. The aim of this studyis to develop a computational tool which permits the analysis and the easy implementation of combustion phenomena for high speed flows. To construct an efficient numerical tool, while maintaining a reasonable accuracy, a semi-implicit numerical method was selected and verified for a hydrogen-air mixture. The numerical approach is based on a time-dependent, finite-volume integration of the governing equations suitably modified for chemical non-equilibrium. The evaluation of the reacting constants based on Gibbs free energy and the Van't Hoff equation allows a very easy implementation of the chemical model used, regardless of its complexity. Calculations were performed with adeguate temporal and spatial resolution for modeling the physical process for pratical calculation. Comparisons with numerical results are used for a verification of the numerical procedur
A Numerical Method for the Study of Fluidic Thrust-Vectoring
No full textThrust Vectoring is a dynamic feature that offers many benefits in terms of maneuverability and control effectiveness. Thrust vectoring capabilities make the satisfaction of take-off and landing requirements easier. Moreover, it can be a valuable control effector at low dynamic pressures, where traditional aerodynamic controls are less effective. A numerical investigation of Fluidic Thrust Vectoring (FTV) is completed to evaluate the use of fluidic injection to manipulate flow separation and cause thrust vectoring of the primary jet thrust. The methodology presented is general and can be used to study different techniques of fluidic thrust vectoring like shock-vector control, sonic-plane skewing and counterflow methods. For validation purposes the method will focus on the dual-throat nozzle concept. Internal nozzle performances and thrust vector angles were computed for several range of nozzle pressure ratios and fluidic injection flow rate. The numerical results obtained are compared with the analogues experimental data reported in the scientific literature. The model is integrated using a finite volume discretization of the compressible RANS equations coupled with a Spalart-Allmaras turbulence model. Second order accuracy in space and time is achieved using an ENO scheme
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