Nonlinear potential analysis techniques for supersonic aerodynamic design

A numerical method based on the conservation form of the full potential equation has been applied to the problem of three-dimensional supersonic flows with embedded subsonic regions. The governing equation is cast in a nonorthogonal coordinate system, and the theory of characteristics is used to accurately monitor the type-dependent flow field. A conservative switching scheme is employed to transition from the supersonic marching procedure to a subsonic relaxation algorithm and vice versa. The newly developed computer program can handle arbitrary geometries with fuselage, canard, wing, flow through nacelle, vertical tail and wake components at combined angles of attack and sideslip. Results are obtained for a variety of configurations that include a Langley advanced fighter concept with fuselage centerline nacelle, Rockwell's Advanced Tactical Fighter (ATF) with wing mounted nacelles, and the Shuttle Orbiter configuration. Comparisons with available experiments were good

Radiation induced precursor flow field ahead of a Jovian entry body

The change in flow properties ahead of the bow shock of a Jovian entry body, resulting from absorption of radiation from the shock layer, is investigated. Ultraviolet radiation is absorbed by the free stream gases, causing dissociation, ionization, and an increase in enthalpy of flow ahead of the shock wave. As a result of increased fluid enthalpy, the entire flow field in the precursor region is perturbed. The variation in flow properties is determined by employing the small perturbation technique of classical aerodynamics as well as the thin layer approximation for the preheating zone. By employing physically realistic models of radiative transfer, solutions are obtained for velocity, pressure, density, temperature, and enthalpy variations. The results indicate that the precursor flow effects, in general, are greater at higher altitudes. Just ahead of the shock, however, the effects are larger at lower altitudes. Pre-heating of the gas significantly increases the static pressure and temperature ahead of the shock for velocities exceeding 36 km/sec

Effects of precursor heating on radiative and chemically reacting viscous flow around a Jovian entry body

The influence of change in the precursor region flow properties on the entire shock layer flow phenomena around a Jovian entry body was investigated. The flow in the shock layer was assumed to be steady, axisymmetric, and viscous. Both the chemical equilibrium and the nonequilibrium composition of the shock layer gas were considered. The effects of transitional range behavior were included in the analysis of high altitude entry conditions. Realistic thermophysical and radiation models were used, and results were obtained by employing the implicit finite difference technique in the shock layer and an iterative procedure for the entire shock layer precursor zone. Results obtained for a 45 degree angle hyperboloid blunt body entering Jupiter's atmosphere at zero angle of attack indicates that preheating the gas significantly increases the static pressure and temperature ahead of the shock for entry velocities exceeding 36 km/sec. The nonequilibrium radiative heating rate to the body is found to be significantly higher than the corresponding equilibrium heating. The precursor heating generally increases the radiative and convective heating of a body. That increase is slightly higher for the nonequilibrium conditions

Significance of shock and body slip conditions on Jovian entry heating

The influence of the body and shock slip conditions on the heating of a Jovian entry body is investigated. The flow in the shock layer is considered to be axisymmetric, steady, laminar, viscous, and in chemical equilibrium. Realistic thermophysical and step-function spectral models are employed and results are obtained by implicit finite-difference and iteractive procedures. The freestream conditions correspond to a typical Jovian entry trajectory point. The results indicate that the effect of the slip conditions is significant when the altitudes are higher than 225 km and that the contribution of a radiative heat-flux term in the energy equation should not be neglected at any altitude

Influence of precursor heating on viscous flow around a Jovian entry body

The influence of changes in precursor region flow properties (resulting from the absorption of radiation from the shock layer) on the entire shock layer flow phenomena was investigated. The axially symmetric case is considered for both the preheating zone (precursor region) and shock layer. The flow in the shock layer is assumed to be viscous with chemical equilibrium but radiative nonequilibrium. Realistic thermophysical and spectral models are employed, and results are obtained by implicit finite difference and iterative procedures. The results indicate that precursor heating increases the radiative heating of the body by a maximum of 7.5 percent for 116 km entry conditions

Effects of precursor heating on chemical and radiation nonequilibrium viscous flow around a Jovian entry body

The influence of precursor heating on viscous chemical nonequilibrium radiating flow around a Jovian entry body is investigated. Results obtained for a 45-degree hyperboloid blunt body entering Jupiter's nominal atmosphere at zero angle of attack indicate that the nonequilibrium radiative heating rate is significantly higher than the corresponding equilibrium heating. The precursor heating, in general, increases the radiative and convective heating to the body, and this increase is slightly higher for the nonequilibrium conditions

CAD-centric Computation Management System for a Virtual TBM

HyPerComp Inc. in research collaboration with TEXCEL has set out to build a Virtual Test Blanket Module (VTBM) computational system to address the need in contemporary fusion research for simulating the integrated behavior of the blanket, divertor and plasma facing components in a fusion environment. Physical phenomena to be considered in a VTBM will include fluid flow, heat transfer, mass transfer, neutronics, structural mechanics and electromagnetics. We seek to integrate well established (third-party) simulation software in various disciplines mentioned above. The integrated modeling process will enable user groups to interoperate using a common modeling platform at various stages of the analysis. Since CAD is at the core of the simulation (as opposed to computational meshes which are different for each problem,) VTBM will have a well developed CAD interface, governing CAD model editing, cleanup, parameter extraction, model deformation (based on simulation,) CAD-based data interpolation. In Phase-I, we built the CAD-hub of the proposed VTBM and demonstrated its use in modeling a liquid breeder blanket module with coupled MHD and structural mechanics using HIMAG and ANSYS. A complete graphical user interface of the VTBM was created, which will form the foundation of any future development. Conservative data interpolation via CAD (as opposed to mesh-based transfer), the regeneration of CAD models based upon computed deflections, are among the other highlights of phase-I activity

CAD-centric Computation Management System for a Virtual TBM

HyPerComp Inc. in research collaboration with TEXCEL has set out to build a Virtual Test Blanket Module (VTBM) computational system to address the need in contemporary fusion research for simulating the integrated behavior of the blanket, divertor and plasma facing components in a fusion environment. Physical phenomena to be considered in a VTBM will include fluid flow, heat transfer, mass transfer, neutronics, structural mechanics and electromagnetics. We seek to integrate well established (third-party) simulation software in various disciplines mentioned above. The integrated modeling process will enable user groups to interoperate using a common modeling platform at various stages of the analysis. Since CAD is at the core of the simulation (as opposed to computational meshes which are different for each problem,) VTBM will have a well developed CAD interface, governing CAD model editing, cleanup, parameter extraction, model deformation (based on simulation,) CAD-based data interpolation. In Phase-I, we built the CAD-hub of the proposed VTBM and demonstrated its use in modeling a liquid breeder blanket module with coupled MHD and structural mechanics using HIMAG and ANSYS. A complete graphical user interface of the VTBM was created, which will form the foundation of any future development. Conservative data interpolation via CAD (as opposed to mesh-based transfer), the regeneration of CAD models based upon computed deflections, are among the other highlights of phase-I activity