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Author

Hiromu Sugiyama

Bio: Hiromu Sugiyama is an academic researcher from Muroran Institute of Technology. The author has contributed to research in topics: Shock wave & Supersonic speed. The author has an hindex of 7, co-authored 43 publications receiving 207 citations.

Papers
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TL;DR: In this article, the wall shear stress distributions on the side, top and bottom walls of a square duct with the Mach 4 pseudo-shock wave were investigated qualitatively by the shear-sensitive liquid crystal visualization method.
Abstract: In this paper, the outline of the Mach 4 supersonic wind tunnel for the investigation of the supersonic internal flows in ducts was firstly described. Secondly, the location, structure and characteristics of the Mach 2 and Mach 4 pseudo-shock waves in a square duct were investigated by color schlieren photographs and duct wall pressure fluctuation measurements. Finally, the wall shear stress distributions on the side, top and bottom walls of the square duct with the Mach 4 pseudo-shock wave were investigated qualitatively by the shear stress-sensitive liquid crystal visualization method. The side wall boundary layer separation region under the first shock is narrow near the top wall, while the side wall boundary layer separation region under the first shock is very wide near the bottom wall.

27 citations

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TL;DR: In this article, the structures and characteristics of X-shaped and L-shaped pseudo-shocks in a square duct were investigated through numerical simulations and experiments at Mach 2 and Mach 4, respectively.
Abstract: The structures and characteristics of λ-shaped and X-shaped pseudo-shocks in a square duct are investigated through numerical simulations and experiments at Mach 2 and Mach 4, respectively. The experiments were carried out in a pressure-vacuum supersonic wind tunnel with a test cross section of 80×80 mm2. Numerical simulations were carried out using the Harten-Yee second-order TVD scheme and the Baldwin-Lomax turbulence model. The Reynolds numbers for the Mach 2 and 4 cases were Re∞=2.53×107 and Re∞=2.36×107, respectively, and the flow confinement was δ∞⁄h=0.35 for both cases. The computational results for the Mach 2 pseudo-shock wave are in good agreement with the experimental results. Based on this agreement, the flow quantities, which are very difficult to obtain experimentally, were analyzed by numerical simulation. Although several differences were found between the computational results and experiments in the case of Mach 4 due to asymmetric characteristics in experiment which could not be reproduced in numerical simulation, the computational results are valuable for understanding this complex asymmetric phenomenon.

21 citations

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TL;DR: In this paper, a catalytic reaction on a platinum wire was conducted spatially to evaluate a mixing condition in a supersonic flow field, which was created by a transverse hydrogen jet injected into a cold super-sonic cross flow (Mach 1.81) through a wedge shaped injector.
Abstract: A new measurement by using a catalytic reaction on a platinum wire was conducted spatially to evaluate a mixing condition in a supersonic flow field. A spatial mixing field was created by a transverse hydrogen jet injected into a cold supersonic cross flow (Mach 1.81) through a wedge shaped injector. The half-vertical angles of 8° or 18° were chosen as that of the wedge shaped injector. These results were compared with that of a circular injector case. The results showed that this method could evaluate a spatial mixing condition. The results also clarified that a jet plume in the cases of wedge injectors penetrated higher than that of the circular injector case and separate from the lower wall when going downstream. To observe jet/supersonic flow interaction, Schlieren visualization and oil flow visualization were carried out. It was shown that the extent of the separation region around the 8° wedge injector was the smallest among those injectors. Pitot pressure measurements were also conducted. These indicated that a wedge injector scheme was more beneficial than that of a circular injector for the supersonic combustion and combustor wall cooling.

16 citations


Cited by
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TL;DR: In this article, the transverse jet in supersonic crossflows has been summarized systematically from four aspects, namely single injection, multiport injection, interaction between jet and vortex generator, and interaction between the jet and shock wave.

216 citations

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TL;DR: In this paper, the effect of the injector geometric configuration on the mixing efficiency of the transverse injection flow field has been investigated, and four different configurations have been considered in the current study, namely the square port, the diamond ports, the equilateral triangular port and the circular port.

132 citations

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TL;DR: In this paper, the effects of the divergent angle and the back pressure on the shock wave transition and the location of the leading edge of the turbojet in a three-dimensional scramjet isolator were estimated and discussed.

132 citations

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TL;DR: In this paper, a brief representation of hydrogen fueled scramjet engine as well as the challenges associated with H2 fuel is discussed thoroughly and the advantage of hydrogen as a fuel as compared to other hydrocarbon fuel is also discussed.

125 citations

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TL;DR: In this article, the main results on the shock train structure and its associated phenomena inside isolators, studied using the aforementioned tools are brought together, and several promising flow control techniques that have more recently been applied to manipulate the shock wave/boundary layer interaction are also examined.

121 citations