AbstractBased on the unsteady viscous flow simulation, the flow characteristics inside the supersonic jet element have been investigated numerically. The corresponding initial switching process has been overall divided into two major stages. The results have shown that the switching process for the supersonic jet flow is an extremely complex process, which can include the complex shock system evolution, the free shear layers together with the boundary layers evolution and multiple vortex region unsteady evolution etc. The presence of the switching oblique shock near the control port is not the necessary condition to make the jet deflect, but its formation is good for the early transverse extension of the stripping vortex zone. A new concept named minimum control mass flow rate has also been proposed and emphasized. The Viscosity and adverse pressure gradient have been found to be the key factors for the occurrence of flow separation to shorten the switching time. The vortex structures at different switching time together with the variations (thrust, static pressure as well as oblique shock waves etc.) inside the supersonic jet element have been obtained computationally and analyzed in details.
HighlightsSwitching oblique shock is good for early transverse extension in stripping vortex zone.Combined thrust is decided by right (initial) and left output thrust (final) respectively.Minimum control mass flow rate concept has been proposed and emphasized.Viscosity and adverse pressure gradient are the key factors for flow separation.
Numerical investigation of switching mechanism for the supersonic jet element
Acta Astronautica ; 136 ; 342-353
2017-03-23
12 pages
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
<italic>F</italic> , total thrust (N) , <italic>e</italic> , dissipation rate (m<sup>2</sup>/s<sup>3</sup>) , <italic>k</italic> , Kinetic energy (m<sup>2</sup>/s<sup>2</sup>) , <italic>f<inf>l</inf></italic> , left outlet thrust (N) , <italic>m</italic> , mass flow rate (K) , <italic>f</italic><inf><italic>r</italic></inf> , right outlet thrust (N) , <italic>Ma</italic> , Mach number , <italic>l</italic><inf><italic>out</italic></inf> , pressure outlet (Pa) , <italic>Ps</italic> , main gas source pressure (bar) , Δ<italic>t</italic> , time step (s) , <italic>T</italic> , temperature (K) , <italic>P</italic><inf><italic>01</italic></inf> , point from main jet inlet (−0.0062,0.042) , <italic>t</italic> , switching time (s) , <italic>P</italic><inf><italic>02</italic></inf> , point from main jet inlet (0.0062,0.042) , Supersonic jet element , Shock wave , Vortex , Shear layer , Switching
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