The shape of arc plasma in gas-shielded welding is an important factor for the quality and efficiency welding. changes its by external magnetic field because a flow electricity subjected to electromagnetic force. In this study, we examined control cusp-type field. produces high low area alternatively, cross-section from circular elliptical shape. previous study using solenoid coils produce reported that magnetized provided deeper penetration. However, device developed cusp was too large...

We present the results of numerical analysis wave drag reduction by a single-pulse energy deposition in supersonic flow field around sphere. The for sphere was reduced as result interaction between low-density core following blast produced and bow shock developed front investigated mechanism terms unsteady induced interaction. effects deposited location on were examined parametric study. From obtained results, we refined parameters, utilizing baroclinic source term that vorticity vortex...

A novel antenna composed of two bent conducting strips (leaves) above a ground plane (designated as the two-leaf antenna, abbreviated BeToL) is investigated to form tilted, linearly polarized, wide H-plane radiation beam. For this, one leaf BeToL (whose height small: approximately 0.1 wavelength) excited and other used parasitic element. First, analysis performed under condition that infinite extent. It can be found realizes desirable tilted beam (HPBW > 150° in H plane) with low cross...

A bent four-leaf antenna (BeFoL) is considered to generate four reconfigurable beams. For this, one end of the leaves excited with others shorted ground plane. The beam direction in elevation plane controlled by size One technique directing horizontal also presented, where finite square bent. It found that front-to-back ratio frequency bandwidth for a 10-dB criterion approximately 43%. Within this band, VSWR less than 2, as desired.

The series of aerodynamic heating test campaigns with blunt shaped models in hypersonic high-enthalpy flow were conducted JAXA-HIEST. Four different applied this study; Apollo CM 6.4% scale model, HRV capsule 6% scaled model and two hemi-sphere probes radius curvature r=20mm r=100mm. Numerical analysis an axis-symmetric Navier-Stokes thermo-chemical non-equilibrium code was also conducted. Stagnation pressure almost fixed to P0=50MPa, while stagnation enthalpy varied from H0=7MJ/kg 21MJ/kg....

A third order accurate cellwise relaxation implicit Discontinuous Galerkin (DG) scheme for RANS simulations using unstructured hybrid meshes is presented. scalar parabolic equation first examined to clarify what really important in construction of matrix keep its diagonal dominance the and fourth DG schemes. In addition, discussions are given approximated reducing computational cost. Then, successfully developed utilizing expertise learned study solving equation. Superior spatial accuracy...

A wind-tunnel test campaign has helped identify the cause of stagnation heat-flux augmentation observed under high-enthalpy and high-pressure conditions in several major shock tunnels. The was carried out free-piston tunnel HIEST enthalpies from H0 = 8 to 20 MJ/kg with pressure P0 50 MPa. flat plate miniature coaxial thermocouples used measure surface-heat flux. To radiation convection heating independently, optical filter windows passing different wavelengths were placed front...

We present the results of numerical simulation laser-induced blast wave coupled with rate equations to clarify unsteady property ionization processes during pulse heating. From comparison quasi-steady computations, plasma region expands more widely, which is sustained by inverse-bremsstrahlung since an equilibrium does not establish at front region. The delayed relaxation leads rapid expansion driving and enhances energy conversion efficiency from a heating laser wave.

A two-dimensional code to simulate the operation of laser-driven in-tube accelerator has been developed. The includes laser ray-tracing and ionization non-equilibrium for an analysis realistic operation. feature blast wave can be reproduced with this process generation laser-induced is analyzed. Moreover, our computational results show that generated shock waves are repeatedly reflected on tube wall projectile base. quantitative comparisons experimental data also presented.

This paper explores an appropriate position for the dust-capturing device on surface of aeroflyby capsule traveling at a velocity in Martian atmosphere altitude 36 km. The equation motion and heat-transfer dust particles are solved particle sizes 0.5 . A thermochemical nonequilibrium flowfield over vehicle is computed using prismatic unstructured mesh method. Analysis indicates that placing leeward frustum edge results less aerodynamic drag lower heat flux than same windward edge. exerted...

Unexpected heat flux augmentation in a free-piston high-enthalpy shock tunnel (HIEST) was numerically analyzed. Since previous experimental study implied that the radiation heating from layer caused augmentation, three-dimensional thermochemical non-equilibrium CFD code including transport calculation developed. This conducted under following models: 1) Radiation air species calculated by solving radiative equation using tangent slab approximation; and 2) impurities such as carbon soot metal...

1Graduate Student, Department of Aerospace Engineering, E-mail: asada@cfd.mech.tohoku.ac.jp, AIAA Member 2Researcher, JAXA institute Aeronautical Technology, kanako.yasue@gmail.com 3Assistant Professor, yogi@rhd.mech.tohoku.ac.jp, 4Professor, sawada@cfd.mech.tohoku.ac.jp, Associate Fellow

A numerical approach to improve prediction capability of transonic buffet onset based on URANS solutions is presented. In the computation unsteady flowfield over NACA0012 wing section, perturbation artificially introduced avoid convergence a pseudo steady solution where phenomenon expected take place. It shown that can be easily determined from variation RMS flowfield. The computed boundary favorably agrees with experimental data.

Understanding the dynamics of laser‐produced plasma is essentially important for increasing available thrust force in a gas‐driven laser propulsion system such as laser‐driven in‐tube accelerator. A computer code developed to explore formation expanding nonequilibrium produced by irradiation. Various properties blast wave driven are examined. It found that propagation substantially affected radiative cooling effect lower density case.

We have developed a two-dimensional numerical code based on PIC-MCC method with representative reactions for N2 to perform discharge dynamics in DBD plasma actuator and estimate generated force resulting from ion-neutral collision. Depending the applied voltage exposed electrode, two types of process are found actuator. The dielectric surface potential changes as time advances by following fact that severely affected electric field. Moreover, resultant thrust collision is several times...