Kazuaki Hatanaka

Background Oriented Schlieren Method Using Multi-scale Periodic Pattern

Background oriented schlieren (BOS) method is an optical visualization technique for flow fields utilizing the phenomenon that the refractive index of fluid changes when a disturbance occurs in the flow field [1, 2].

Experimental Investigation of Unsteady Shock Oscillation by a Forward-Facing Hemisphere at Mach 3

Experimental and numerical investigation has been made to reveal the characteristic of shock wave pulsation in front of a hemi-spherical model at supersonic speeds more above Mach 2. Three types of measurements by; high-speed schlieren, pressure transducers, and pressure-sensitive paint, were employed to make the relation between shock pulsation and pressure distribution on the inner surface of the model clear. Three-dimensional numerical analysis has also been carried out on the flow field around the model by using compressible fluid analysis code FaSTAR, which was developed by JAXA. Comparison between the experimental results and the numerical one summarized that the shock wave pulsation with about 800 Hz was initiated by the small disturbances generated by the bow shock in front of the model and developed inside it. The development of the small disturbances depends on the geometric configuration of the rip of the model. A new geometrical configuration of supersonic parachute for planetary probes would be proposed to suppress shock pulsation at decent phase into the planet atmosphere.

Investigation of Nozzle Starting Problem and Its Application to Construct a Supersonic Wind Tunnel

Shock tubes are commonly used for investigating supersonic/hypersonic flows. Basic types of them use diaphragms of different materials such as a plastic sheet or a metal plate depending on the facility. Diaphragms break relatively quick and a shock wave forms with shorter distances compared with more sophisticated shock tubes.

Large Deformation of Bow Shock Waves Ahead of a Forward-Facing Hemisphere

Aerodynamic deceleration devices including parachute have been widely used not for recovery system in atmospheric of the Earth but for entry system in that of other planet of solar system

Numerical Predictions of Influence of Boundary Layer on Hemispherical Imploding Shock Focusing

In the early 1960s,Glass proposed and constructed a hemispherical implosion chamber that could produce extremely high pressure/temperature conditions at its geometric focal point [1]

Numerical and Experimental Investigations of Fluidic Thrust Vectoring with Oblique Shock Waves

Mechanical thrust vectoring (MTV) has already been put to practical use. It controls the thrust direction of jet propulsion system by mechanically moving structural components such as exhaust nozzles and paddles. MTV has several advantages such as high mobility during supersonic flight in the high-altitude where effective turning is difficult to perform due to low atmospheric density.

Computations of Flow Field around an Object Decelerating from Supersonic to Subsonic Velocity

A detached shock wave is formed in front of a blunt object moving with supersonic velocities or an object placed in a supersonic flow. The distance fromthe shock front to the surface of the moving body is called the shock stand-off distance, δ , and is measured along the propagation axis when the object is a solid sphere.