The Mechanism of Pseudo-Shock Waves

Ikui, Takefumi; Matsuo, Kazuyasu; Nagai, Minoru

doi:10.1299/jsme1958.17.731

Cited by 90 publications

(36 citation statements)

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“…The distance from the diaphragm to the point at which the shock wave is generated is called the shock formation distance. The theoretical value of the shock formation distance L S W is calculated using the simple theory of shock tube (7) . Under the conditions adopted in this research, the value of L S W is 290 mm.…”

Section: Nickel-platinum Double-wire Probementioning

confidence: 99%

“…After the shock wave, the pressure increased to about 30 kPa. Using the simple theory of shock tube (7) , the theoretical value of the pressure behind the shock wave was calculated under the conditions of this experiment: initial pressure in the wind tunnel of 10 kPa and pressure ratio of the high-pressure chamber and the low-pressure wind tunnel of 10 to 1. The theoretical value was 28.2 kPa.…”

Section: Process Of Experimentsmentioning

confidence: 99%

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Research on Dynamic Response of Catalytic Heat Release Rate on Platinum Wire to a Shock Wave in Hydrogen-Air Mixture

Nakamura

Nagata

Totani

et al. 2005

JSME international journal. Ser. B, Fluids and thermal engineer

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The authors have proposed the use of a hydrogen concentration probe as a new simple method of evaluating hydrogen concentration. We propose a method of evaluating the rate of change of catalytic heat release in order to evaluate hydrogen concentration history for the condition under which the boundary layer is likely to be immature. By using a shock tube, the rate of increase of heat budget of platinum wire was investigated experimentally. Experimental results indicate that the rate of increase of difference due to catalytic heat release is the maximum value when the hydrogen concentration is 30%, which agrees well with a previous result. As a result, this method can be used to evaluate the rate of increase of difference due to catalytic heat release. It is clear that the rate of change due to catalytic heat release is strongly correlated with the rate of change of hydrogen concentration.

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Section: Nickel-platinum Double-wire Probementioning

confidence: 99%

Section: Process Of Experimentsmentioning

confidence: 99%

Research on Dynamic Response of Catalytic Heat Release Rate on Platinum Wire to a Shock Wave in Hydrogen-Air Mixture

Nakamura

Nagata

Totani

et al. 2005

JSME international journal. Ser. B, Fluids and thermal engineer

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“…2,[7][8][9] Crocco proposed a shockless model. 2 In his model, the dissipative region spreads toward the isentropic region.…”

Section: Introductionmentioning

confidence: 99%

“…As for the length of the pseudo-shock, many researchers tried to present a way of estimation of the length. Ikui and others have presented modifications 7,8 to the Crocco model and have estimated length of the pseudo-shock. Zimont and Ostras have also presented a modification 9 of the Crocco model.…”

Section: Introductionmentioning

confidence: 99%

Momentum Balance Model of Flow Field with Pseudo-Shock

Kanda

Tani

2005

43rd AIAA Aerospace Sciences Meeting and Exhibit

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The length of a pseudo-shock was estimated with a new momentum balance model. In this simple model, it is presumed that there is no wall friction in the region of the pseudo-shock. Inflow conditions are specified at a boundary sufficiently upstream of the pseudo-shock. The outflow boundary condition is applied with, for example, specified pressure or choking. The outflow impulse function is balanced with the inflow impulse function, the wall friction upstream of the pseudo-shock, and the reaction force from the wall. The starting position of the pseudo-shock is determined through balance of the forces in this model, and the length of the pseudo-shock is also determined. The model was applied to several kinds of flow fields, for example, straight ducts with and without a backward-facing step, and divergent ducts. The model was also applied to the diffuser of an ejector-jet, in which two gases flowed in parallel. The calculated results reasonably agreed with the experimental results within the scope of preliminary application. The starting position of the pseudo-shock was primarily dominated by the reaction force in the divergent duct. Several features of the pseudo-shock were discussed with the present model. (7) and (17) a = papameter of Eq. (7) B = parameter of Eqs. (7) and (17) 2 JAXA Research and Development Report JAXA-RR-06-037E e = outflow f = friction i = inflow p = pseudo-shock, state at the exit of pseudo-shock r = reaction step = step t = total th = throat w = wall 1 = upstream of pseudo-shock, entrance, primary flow 1b = after bleeding and upstream of pseudoshock 2 = downstream of pseudo-shock, secondary flow

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“…Therefore, study of the PSW is very important in engineering applications. Several researchers have investigated the structure and characteristics of the PSW experimentally, including Ikui et al, 2) Sugiyama et al [3][4][5][6] and Carroll and Dutton, 7) and through numerical simulations, for example Hataue,8) Carroll et al 9) and Yamane et al 10) However, several important flow quantities of the PSW could not be measured via experimental methods, and numerical simulations have not agreed well with the experimental findings. Therefore, the detailed structure, characteristics, and turbulence phenomena of the PSW have not been fully clarified.…”

Section: Introductionmentioning

confidence: 99%

Numerical and Experimental Investigations on Mach 2 and 4 Pseudo-Shock Waves in a Square Duct

Sun

Sugiyama

Mizobata

et al. 2004

Trans. Japan Soc. Aero. S Sci.

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The structures and characteristics of -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 Â 80 mm 2 . 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 1 ¼ 2:53 Â 10 7 and Re 1 ¼ 2:36 Â 10 7 , respectively, and the flow confinement was 1 =h ¼ 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.

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The Mechanism of Pseudo-Shock Waves

Cited by 90 publications

References 0 publications

Research on Dynamic Response of Catalytic Heat Release Rate on Platinum Wire to a Shock Wave in Hydrogen-Air Mixture

Research on Dynamic Response of Catalytic Heat Release Rate on Platinum Wire to a Shock Wave in Hydrogen-Air Mixture

Momentum Balance Model of Flow Field with Pseudo-Shock

Numerical and Experimental Investigations on Mach 2 and 4 Pseudo-Shock Waves in a Square Duct

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