Begell House Inc.
TsAGI Science Journal
TSAGI
1948-2590
48
6
2017
ON A BOUNDARY LAYER IN A SEPARATED FLOW REGION
493-504
10.1615/TsAGISciJ.2018025788
Georgy Lvovich
Korolev
Central Aerohydrodynamic Institute (TsAGI) 1, Zhukovsky str., Zhukovsky, 140180, Moscow region, Russia
Victor Vladimirovich
Sychev
Central Aerohydrodynamic Institute (TsAGI), 1, Zhukovsky Str., Zhukovsky, Moscow Region, 140180, Russia
boundary layer
free streamlines
marginal separation
A plane steady symmetric flow of incompressible fluid around a thin rhomb at zero angle of attack is considered at high Reynolds numbers. A numerical solution to the Prandtl boundary layer equation for a slow flow inside the separation region is found. The rhomb thickness is determined at which the
removable singularity appears in this solution.
SELF-SIMILAR SOLUTIONS OF THE JEFFERY–HAMEL TYPE FOR COMPRESSIBLE VISCOUS GAS FLOW
505-514
10.1615/TsAGISciJ.2018025813
Murad Abramovich
Brutyan
Central Aerohydrodynamic Institute (TsAGI), 1 Zhukovsky Str., Zhukovsky 140180, Russia
Navier–Stokes equations
viscous gas flow
exact solutions
A plane flow of viscous gas from a source/sink located at the wedge vertex is considered. Criteria for the existence of self-similar solutions of the Jeffery–Hamel type for a source flowing from the vertex of a wedge with heat-insulated walls and a wedge with a given wall temperature are established. In a special case, in which the gas temperature is constant along the streamlines and the transport coefficients are power functions of the temperature, analytical solutions are obtained.
SIMULATION OF THE FLOW IN AIRCRAFT COMPLEX PNEUMATIC LINES
515-533
10.1615/TsAGISciJ.2018025533
Andrey Aleksandrovich
Efremov
Central Aerohydrodynamic Institute (TsAGI), 1, Zhukovsky Str., Zhukovsky,
Moscow Region, 140180, Russia
pneumatic line
graph
numerical simulation
Navier–Stokes equation
hydrodynamic drag
dynamic performance
A numerical simulation method of the flow in complex (branched and multi-component) pneumatic lines used in contemporary aircraft is presented. The method is based on integrating the crosssectional averaged Navier–Stokes equation and applying empirical data to the hydrodynamic losses in various elements of pneumatic lines. A comparison of the results of the calculations and experimental studies of real pneumatic lines of a maneuverable aircraft is given, and good agreement is shown.
INVESTIGATIONS OF VOLUME-CENTERED DISCHARGE IN AIR SUPERSONIC FLOW WITH ADDITIONAL PROPANE AND OXYGEN INJECTION
535-549
10.1615/TsAGISciJ.2018025534
Vyacheslav Konstantinovich
Alatortsev
Central Aerohydrodynamic Institute (TsAGI), 1 Zhukovsky Str.,
Zhukovsky, Moscow Region, 140180, Russia
Sergei Ivanovich
Inshakov
Central Aerohydrodynamic Institute (TsAGI), 1, Zhukovsky Str., Zhukovsky,
Moscow Region, 140180, Russian Federation
Ivan Sergeevich
Inshakov
Central Aerohydrodynamic Institute (TsAGI), 1 Zhukovsky St., Zhukovsky, Moscow Region, 140180, Russia
Aleksandr Fedorovich
Rozhkov
Central Aerohydrodynamic Institute (TsAGI), 1 Zhukovsky Str.,
Zhukovsky, Moscow Region, 140180, Russia
Vladimir Vladimirovich
Skvortsov
Central Aerohydrodynamic Institute (TsAGI) 1, Zhukovsky str., Zhukovsky, 140180, Moscow region, Russia
Andrey Yuryevich
Urusov
Central Aerohydrodynamic Institute (TsAGI), 1 Zhukovsky Str., Zhukovsky,
Moscow Region, 140180, Russian Federation
Aleksandr Aleksandrovich
Uspenskii
Central Aerohydrodynamic Institute (TsAGI), Zhukovsky str. 1, Zhukovsky, Moscow Region, 140180 Russia
supersonic flow
volume-centered discharge
propane and oxygen injection through anode
spectroscopic studies
flow pattern
The flow arising in a volume-centered non-equilibrium discharge channel with propane and oxygen jet injection through an anode into supersonic airflow was investigated by the emission spectroscopy method. The experiments were carried out at M = 2, static pressure values of ~ 2.9 × 104 Pa (217 Torr) and 5.33 × 104 Pa (400 Torr), and discharge current in the range from 1 to ~ 1.85 A. Data on the composition and spatial distribution of the emission intensity of the reaction products, which appeared in the transformation process of the air–fuel mixture in the discharge region, were obtained. In particular, data on the CN, OH, and C2 emission intensity distributions and those for atomic hydrogen and oxygen are presented. The performed investigations allowed answering the question about the influence of the type of injecting components, methods of injection, and current values on the plasma chemical reaction intensities.
COMPARISON OF FLIGHT PATH OPTIMIZATION PROBLEM SOLUTIONS BY DIRECT AND INDIRECT METHODS FOR A GUIDED AIRCRAFT MISSILE WITH A ROCKET ENGINE
551-563
10.1615/TsAGISciJ.2018025535
Sergey Alekseyevich
Lyovin
Central Aerohydrodynamic Institute (TsAGI), 1, Zhukovsky Str., Zhukovsky,
Moscow Region, 140180, Russia
flight path optimization
direct method
indirect method
polynomial method
direct collocation
multiple shooting
Two solutions to the problem of optimizing the flight path of an aircraft are compared: the first solution was obtained by the direct method, and the second solution satisfies the necessary optimality conditions. A brief description of the polynomial method (direct method) and a combination of the
direct collocation and multiple shooting methods (including elements of the direct and indirect methods) is given, which is used to solve the aircraft flight path optimization problem from a given initial point to a given final point using the minimum flight time criterion. The aircraft is an air-to-surface missile with a solid-propellant rocket engine. The investigations showed that both methods yield
close results in terms of phase variables, control variables, and criterion values. This allows drawing
the conclusion that the polynomial method solves the problem under consideration with sufficient accuracy.
APPLICATION OF THE POLYNOMIAL RITZ METHOD FOR ANALYZING DYNAMIC AEROELASTICITY CHARACTERISTICS BY TAKING INTO ACCOUNT GYROSCOPIC FORCES
565-577
10.1615/TsAGISciJ.2018025714
Fanil’ Zakievich
Ishmuratov
Central Aerohydrodynamic Institute (TsAGI), Zhukovsky St. 1, Zhukovsky, 140180, Russia
Anton Gennadievich
Kuznetsov
Central Aerohydrodynamic Institute (TsAGI), 1, Zhukovsky Str., Zhukovsky,
Moscow Region, 140180, Russian Federation
Valeriy Arkadievich
Mosunov
Central Aerohydrodynamic Institute (TsAGI), Zhukovsky str. 1, Zhukovsky, 140180, Russia
aeroelasticity
gyroscopic forces
flutter
polynomial Ritz method
aeroservoelasticity
This paper describes the development of a method for calculating dynamic aeroelasticity characteristics (eigenfrequencies, flutter, dynamic response, and aeroservoelasticity) by taking into account gyroscopic forces using the polynomial Ritz method. An example of the destabilizing influence of gyroscopic forces on the flutter and aeroservoelasticity characteristics of an airplane with engines located on pylons under the wing is presented.
NUMERICAL METHODS FOR DETERMINING TORSIONAL STIFFNESS OF PRISMATIC RODS
579-595
10.1615/TsAGISciJ.2018025651
Vladimir Mikhailovich
Uskov
Central Aerohydrodynamic Institute (TsAGI), 1, Zhukovsky Str., Zhukovsky,
Moscow Region, 140180, Russian Federation
Aleksandr Vasilievich
Chedrik
Central Aerohydrodynamic Institute (TsAGI), 1, Zhukovsky Str., Zhukovsky,
Moscow Region, 140180, Russian Federation
Vasilii Vasil'evich
Chedrik
Central Aerohydrodynamic Institute (TsAGI), Zhukovsky St. 1, Zhukovsky 140180, Russia
Saint-Venant problem
torsional stiffness
numerical methods
Laplace equation
Poisson equation
numerical studies
Numerical methods for solving the Saint-Venant problem on torsion of a rod with an arbitrarily shaped cross section are considered. A comparative analysis of these methods is performed for two cross sections that have the exact analytical solutions and complicated cross sections of practical significance. Various approaches are developed for solving the Laplace and Poisson equations for the
torsion problem. The Poisson equation is solved by the finite-element method with different orders of
interpolation of the stress function. The solution to the Neumann problem is searched in the form of harmonic polynomials. The method of fundamental solutions is used to solve the Dirichlet problem for the Laplace equation. Numerical results for determining torsional stiffness are compared with available experimental data.