Annotation: A promising experimental bench – a shock wind tunnel was put into operation at Yuzhnoye SDO. The shock wind tunnel is designed to simulate the incident flow during rocket flight at high supersonic and hypersonic velocities. To solve actual design problems facing Yuzhnoye SDO, it was necessary to expand the range of velocities under investigation in a shock wind tunnel by low supersonic Mach numbers (Mа=1.5; 2; 3). As a result of this work, a modernized configuration of the shock wind tunnel was developed, which allows simulating flow parameters at low supersonic velocities. The results of aerodynamic experiment performed in the modernized shock wind tunnel, which are close to full scale ones, can be obtained using as much data on peculiarities of supersonic flow formation in it as possible. Therefore, the study of the distribution of Mach numbers profiles in the working section of the modernized shock wind tunnel at low and high supersonic velocity was chosen as the main line of research. The results of the research presented in the article are based on the use of numerical simulation methods, as well as data obtained experimentally. As a result of gasdynamic simulation of a supersonic flow conducted for the nozzle Mа=4 and the nozzle Mа=2, the calculated and experimental data on the distribution pattern and field values of Mach numbers in the working section of the tunnel were obtained. A comparative analysis was carried out. The boundaries of the region of equal velocities, within which the condition of quasistatic supersonic flow is satisfied, and the lifetime of the operating mode for the selected nozzle type were determined. At the flow from the nozzle Mа=2, a peculiarity was revealed in the distribution pattern of Mach numbers fields associated with the appearance of “blocking” effect of the supersonic flow. The methods for eliminating the effect of flow “blocking” at low supersonic velocities are proposed.

Annotation: The tubes of rectangular section made of composite material find ever- growing use. Winding of tubes without using dowels for small winding angles has a number of disadvantages. The technology of winding through dowels does not have these disadvantages. The paper presents the authors-developed calculation technique for programs of winding the tubes of rectangular section made of composite materials using dowels. To ensure winding continuity, the dowels at base must have equal distances between them. The external diameter of comb is selected with margin taking into account band stranding on the dowels. The scheme of winding on entire layer is determined that represents a table which indicates band position between the dowels of front and rear comb during winding a layer for each coil. Then the coordinates of machine tool are determined. For this purpose, we determine the angles of coil winding, corresponding angles of mandrel turn in determined coordinates X, the coordinates of band escape point, angle of inclination of free section of band, then from geometrical considerations we obtain the components of unit vector of tangent to reinforcing trajectory and directly the coordinated of machine tool actuators. As a result, we obtain the table of coordinates of machine toll actuators during winding of the first coil (at forward and back travel). Using the presented logics, similarly it is easy to obtain for all coils the coordinates of machine tool actuators. According to this technique, the Vitok auto-programming system was developed in MathCad environment. The Vitok system was used during development of winding program for tube 28x28x2 mm under Sich-2M program. The programs operated successfully. The test samples of tubes were wound. The authors performed winding of the tubes of rectangular section made of composite material to obtain a structure with zero linear thermal expansion coefficient.

Annotation: The article considers the procedure for evaluation of acoustic stressing parameters at the observation point nearby the launch vehicle nose cone when passing the sectors with maximum velocity heads and close to 1 Mach numbers. And the problem is set to determine the overall sound pressure level and the corresponding levels in octave and 1/3-octave frequency bands. Procedure under consideration is based on the semi-empirical dependency of characteristics of the wideband aerodynamic noise, which occurs during the launch vehicle flight at high velocities due to the turbulent pressure fluctuations and dimensionless aerodynamic parameters of the main stream. General idea of this approach is to establish relation of the velocity heads with wall pressure fluctuations in the boundary layer, calculating shear stress (friction) on the shell surface based on relationships applicable in the boundary layer theory and engineering experience. Attempts of development of similar calculation models go back to the early efforts, dedicated to the study of the aeroacoustics of the launch vehicle in flight. Main advantages of the procedure are its simplicity and versatility since it can be used to determine the acoustic loads around the payload fairings of launch vehicles of different sizes and shapes within the wide range of flight velocities and altitudes.