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Results of a numerical study of supersonic flows formed in channels with a square cross section are reported. Configurations consisting of a constricting entrance section formed by four compression wedges aligned at a right angle to each other and a subsequent channel with a constant cross section are considered. The initial shock waves formed on the nose compression wedges pairwise intersect each other in dihedral corners of the configuration along the swept lines, and a complex system of reflected and subsequent interacting shock waves of the general three-dimensional position is formed further downstream. The data are obtained in a supersonic range of freestream Mach numbers M = 2–4 for compression wedge angles of 3° and 8° in flows with both regular and irregular interaction of the initial shock waves in dihedral corners of the configuration. [ABSTRACT FROM AUTHOR]

The paper presents the results of a numerical study of gas dynamics and integral parameters of the flow at the channel entrance located behind a conical or plane shock wave. The freestream Mach number range is M = 2–4 and the range of the angles of the compression surfaces of the wedge and cone is δ= 10–90°. Data on the flow structure at the channel entrance, mass-averaged Mach numbers, total pressure loss coefficient, and flow rate coefficients are obtained. A comparative analysis of these parameters is performed, and the advantages and drawbacks of the channel entrance positions in various types of the flow are noted. [ABSTRACT FROM AUTHOR]

The paper presents the results of a numerical simulation of conditions for starting a supersonic air intake using the bypass of part of the captured air through longitudinal slots. The air-intake duct consists of a narrowing entrance section and a constant-cross-section throat, both elements being constructed using flat surfaces, and the air intake contains longitudinal slots stretching along the lower flat surface. Various variants of the sectional bleeding of air are investigated, and changes in the flow structure in the intake duct depending on the air bleeding variant are demonstrated. Numerical modeling of the three-dimensional flow was performed for free-stream Mach number M∞ = 4 on the basis of Reynolds-averaged Navier-Stokes equations and the k−ω SST model of turbulence. [ABSTRACT FROM AUTHOR]

Results of numerical simulations of a supersonic flow in a channel with a rectangular cross section having a longitudinally ribbed bottom surface are reported. The channel contains a tapered inlet section, where the cowl lip generates a shock wave incident onto the bottom surface, and a posterior constant-area section. The present numerical simulations are performed for a viscous three-dimensional flow with the use of the Reynolds-averaged Navier-Stokes equations and k-ω SST turbulence model. The computations are performed for the free-stream Mach number M = 4. [ABSTRACT FROM AUTHOR]

Results of a numerical study of the flow structure in the rectangular duct of a model air inlet with the interaction of the shock wave generated by the inlet cowl with the turbulent boundary layer on the inner duct surfaces are reported. A configuration involving a convergent entrance section and a constant-cross-section throat was analyzed. The numerical simulation of the three-dimensional flow with free-stream Mach number M = 4 was performed on the basis of the Reynolds-averaged Navier-Stokes equations and the k-ω SST model of turbulence. As a result of the calculations, the limit streamlines and the distributions of static pressure on the duct surfaces, as well as the distributions of total pressure and the fields of Mach number in duct cross sections were obtained. The structure of the flow is analyzed and the possibility of occurrence of longitudinal vortex structures in the corner region of the intake-duct throat is shown. [ABSTRACT FROM AUTHOR]

The results of the numerical modeling of the supersonic flow in an axisymmetric duct in which a pseudo-shock arises are presented. The duct includes the frontal inlet with a funnel-shaped part of initial compression of the supersonic flow and with a cylindrical throat part as well as the subsequent (cylindrical or diverging) diffuser where the flow slows down to a subsonic velocity. The flow conditions at the freestream Mach number M = 6 have been considered. Numerical computations of the flow have been done using a Navier-Stokes equations code and the k-ω SST turbulence model. As a result of computations, such flow parameters have been determined as the location of the pseudo-shock beginning, the length of the pseudo-shock supersonic part, the pressure distribution on the duct wall, the total pressure losses as well as the characteristics of flow turbulence. In particular, the variation of the turbulence intensity and turbulent viscosity along the pseudo-shock length have been examined and, based on these characteristics, the possibility of determining the location of a cross section, in which the pseudo-shock can be treated as completed, have been considered. [ABSTRACT FROM AUTHOR]

The results of the numerical modeling of a flow with a pseudo-shock in an axisymmetric duct are presented. The duct included a frontal inlet with the initial funnel-shaped compression part and the cylindrical throat part as well as the subsequent expanding diffuser. To create a flow with a pseudo-shock, the duct was throttled with the use of the outlet converging insert. Numerical computations of the axisymmetric flow have been conducted on the basis of the solution of the Reynolds-averaged Navier−Stokes equations and with the use of the k-ω SST turbulence model. As a result of computations, such parameters of the flow were determined as the location of the beginning of the pseudo-shock, the length of its supersonic part, the velocity profiles in different cross sections of the pseudo-shock, the pressure distribution on the duct wall, the total pressure recovery factor, and others. The behavior of these parameters at the freestream Mach number М = 6 was analyzed versus the diffuser opening angle and different degree of the inlet duct throttling. [ABSTRACT FROM AUTHOR]