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The present paper describes an experimental and numerical works to investigate a noise phenomenon in supersonic flow that are discharged from a convergent-divergent nozzle with a constant area duct. The noise phenomenon of flow is generated by an emission of acoustic tones. The results obtained shows that unlike the frequency of the screech tone due to the shock-cell structures in the jet flow, the one of the acoustic tone due to the shock wave in the nozzle increases proportional to the nozzle pressure ratio. The frequency of the acoustic tone is depending on the distance from the shockwave to nozzle exit.

A plug nozzle has been studied as a promising nozzle from a viewpoint of improving thrust efficiency for rocket or space plane. In the field of mechanical engineering, supersonic jets from a Laval or a conical nozzle are frequentlry used as a cleaning tool, cooling tool, mixing tool, etc. The plug nozzle also has possibility applicable to the field of mechanical engineering as well, however, the jet structure of the plug nozzle is now well known. The purpose of this paper is to clarify the structure of jets from a plug nozzle by solving Euler equations numerically. The jet flowfield is computed for an axisymmetric plug with a design Mach number 2.0, and the velocity distributions on jet center line are obtained for the over, correct and underexpanded supersonic jets. The structures of the jets issuing from a plug nozzle are highly complicated and are found to be quite different from the jets from a Laval nozzle.

A particle-laden channel flow has been simulated by a large eddy simulation, which is expected to have a substitutability for DNS in order to make $kappa-epsilon$ model for suspension flow minute. The numerical results for the fluid turbulence modulation due to particles are strongly depends on how exact the particle motion is described, especially particle/wall interaction and interparticle collision. In addition to that, it is necessary to modify the sub-grid scale (SGS) turbulence model to take the interaction between particle and small scale turbulence into account. The effort of modification of SGS scale model, however, might cause the same difficulties as the suspension $kappa$-$epsilon$ model development This paper proposes LES model for the gas-solid suspension flow by using Localized Dynamic $kappa_{SGS}$ Equation Model, which can determine model constants dynamically and has possibility of considering back-scatter energy transfer including particulate medium. The proposed model is applied to prediction of a channel flow experiment by Kulick et al.

Although extensive work has been reported on the supersonic free jet, the influence of nozzle geometry on its characteristics, such as on the Pitot pressure distribution, is not well known. The purpose of the present paper is to develop a numerical simulation code that predicts the characteristics of supersonic free jets including the effect of nozzle geometry. The jet flowfield is computed for the nozzle with the design Mach number of 1.5, and the pressure distributions are obtained for the correct and underexpanded supersonic free jets.

In this paper, numerical analysis of laminarization phenomena of strongly heated gas flows within concentric annular tube was performed and an improvement of the Reynolds stress turbulence model is proposed. In the first part, the Reynolds stress model proposed by Launder and Shima was tested in its original form. Numerical results show that the main features of laminarizing flows such as a change in time averaged velocity profiles and the reduction in turbulent kinetic energy can be reproduced to a certain extent. However, it was also found that if the heating rate is relatively low, the prediction efficiency of local Nusselt numbers are considerably poorer than expected. Therefore, it was anticipated that there remains much for the improvement of the original model particularly for the low Reynolds number region. Following these results, an attempt was made to improve the model by reforming the shape of the empirical function that appears there for taking into account the effects of the wa11. The modified model was applied to the case of relatively low heating rate and the considerable betterment was achieved.

The oscillatory characteristics of a pseudo-shock wave with an incoming Mach number of 1.75 in a rectangular straight duct are experimentally investigated by static pressure measurements both on the duct axis and on the wall surface. Statistical analysis is applied to the detailed fluctuating pressure data in the pseudo-shock region. The correlation between the oscillatory characteristics and the flow mechanism of the pseudo-shock wave is also discussed in detail in the last part of the present paper.

The purpose of the present paper is to report a discharging method of high pressure exhaust gas by means of a shock wave confinement in a duct. The duct, which is connected to an exhaust gas pipe, has inlet and exit orifices so that the flow is doubly choked at these sections. For analytical purposes, the flow in the duct is assumed to be a fanno flow with a normal shock wave. The calculated results show that the total pressure reduction increases with a decreasing opening area of the inlet orifice, and the shock wave confinement in the duct can be achieved by decreasing the opening area of the exit orifice. An experimental investigation has also been performed using a shock tunnel, and the experimental results show the validity of the present discharging method.

In the case of rapid expansion of steam in supersonic nozzle on the assumption that the steam is perfect thermally and carolically, the phenomenon for non-equilibrium condensation in two-dimensional inviscid steady state flow has been studied in this paper. Also, changing of variables of the state in nozzle, onset of condensation, generation and phenomenon of condensation shock wave are investigated by the method of chracteristics when the state is changed with degree of superheat and nozzle shape. The phenomenon of onset of condensation is dependent upon shape of nozzle strongly. The smaller radius of curvature of nozzle， the configuration of onset of condensation is the more curved. The lower degree of superheat and the smaller radius of curvature of nozzle (that is, the larger drop of temperature), the generation position of condensation shock wave is the closer to the nozzle throat and the strength of condensation shock wave is the stronger.

The purpose of the present paper is to report the numerical analysis of diffracting shock wave around a sharp-edged corner. The unsteady and nonviscous two-dimensional equations are solved with the piecewise liner method (PLM). The calculated results show that the diffracting shock waves around a corner have been classified into four types. Namely, they are normal, kink, Mach reflection and regular reflection types. The relation between the third shock wave and the vortex has been discussed. Furthermore, the calculated distribution of the pressure along a wall agrees with the experimental data, and the stagnation point on a wall has been observed.

This paper deals with the laminar-flow heat transfer to a fluid flowing axially between a square array of heated cylinders with a uniform surface temperature. The finite-difference form of the energy equation is solved numerically to obtain the axial variation of temperature distribution by means of a forward-marching, implicit method with iteration, and typical results for the arithmetic mean Nusselt number Nu_ are presented graphically for the Graetz number Gz up to 10^5 and spacing-to-diameter ratios σ of 1.0 to 4.0. Furthermore, the numerical results of Nu_ are compared at the same values of volume fraction of cylinders ε with those obtained previously for a triangular array of cylinders with a uniform surface temperature. It is realized that, in general, the rate of heat transfer for the triangular array is higher than that for the square array, especially for the case ε>0.5.

It is well known that when a shock-boundary layer interaction is comparatively strong, the shock in a duct extends over a great distance, which is called a pseudo-shock wave. Many investigations have been reported so far on pseudo-shocks. In these studies, however, the flow in pseudo-shock region was considered as a black box and only the flow properties across the shock were discussed. In the present paper, the flow mechanism in pseudo-shock region is experimentally investigated, especially for the flow field between the first- and the third-shocks composing a pseudo-shock. As the result, it is clarified that, in the flow region under the bifurcated foot of the first shock, which was considered to be a uniform flow region, the flow is decelerated along the streamwise direction. Taking into account the fact described above, the mechanism of generation of the second-shock is discussed in detail.