Begell House Inc.
TsAGI Science Journal
TSAGI
1948-2590
41
4
2010
MATHEMATICAL MODEL OF THE AIRCRAFT AERODYNAMICS IN A VORTEXWAKE
365-384
10.1615/TsAGISciJ.v41.i4.10
Yuriy Nikolaevich
Sviridenko
Central Aerohydrodynamic Institute (TsAGI) 1, Zhukovsky str., Zhukovsky, 140180, Moscow region, Russia
Aleksandr Marksovich
Gaifullin
Central Aerohydrodynamic Institute (TsAGI), 1, Zhukovsky Str., Zhukovsky, Moscow Region, 140180, Russian Federation
aircraft
vortex wake
neural networks
The process of generation and evolution of the vortex wake behind an aircraft in the turbulent atmosphere is considered. An approach to creation of a mathematical model of the aircraft aerodynamics during in-flight refueling based on the use of artificial neural networks is proposed. The accuracy and speed of the flight simulator software modules were estimated while modeling the in-flight refueling.
GROUP VELOCITY OF UNSTABLEWAVES IN A BOUNDARY LAYER AT SUPERSONIC SPEEDS
385-395
10.1615/TsAGISciJ.v41.i4.20
Vladimir Aleksandrovich
Kuzminsky
Central Aerohydrodynamic Institute (TsAGI) 1, Zhukovsky str., Zhukovsky, 140180, Moscow region, Russia
boundary layer
hydrodynamic stability
space disturbances
calculation
Considered in this paper is a hydrodynamic stability of flow in a flat-plate boundary layer for incident flow Mach numbers M = 2.2 and M = 4.5 with displacement-thickness Reynolds numbers and Reδ* = 10,000 (Rex ≅ 0.896 × 106), respectively. Dependence of the group velocity vector on the wave vector absolute value K and the tilt angle ψ of the oblique wave vector for first and second stability modes were derived for the most increasing space disturbances. Amplification coefficients for the second mode at 0 ≤ ψ ≤ 20° are greater than maximum values for the first mode. Variation of group velocity with wave vector has a qualitatively different character for first and second modes, and it has a minimum value for the most increasing second-mode disturbances in the instability region. The direction of group velocity, which is the direction of amplification, varies from −1 to 2° in the instability region and coincides with the direction of incident flow at ψ = 0, 45 and 90. Presented here is a calculation of group velocity absolute value on the assumption of linear dependence between viscosity and temperature and with use of the Sutherland formula. The dependence between group velocity vector and tilt angle ψ of the oblique wave vector was obtained at M = 2.2 for the first mode. In this case, the direction of group velocity in the instability region varies from −6 to 4° and coincides with the direction of incident flow at values ψ = 0 and ψ ≅ 50°.
INVESTIGATION OF PRE-SEPARATED FLOW IN AXISYMMETRICAL DIFFUSER
397-408
10.1615/TsAGISciJ.v41.i4.30
Georgy Lvovich
Korolev
Central Aerohydrodynamic Institute (TsAGI) 1, Zhukovsky str., Zhukovsky, 140180, Moscow region, Russia
boundary layer
diffuser
interaction
separation
A procedure of the axisymmetrical diffuser construction is developed for incompressible liquid flows at high Reynolds numbers with prescribed characteristics of pressure distribution on their surfaces and small frictional losses inside the diffuser. The numerical solution of the problem taking into account the influence of the boundary-layer thickness on the external nonviscous flow is obtained, and the influence of variation of design conditions for the flow parameters in the inlet cross section on the characteristics of the flow in the diffuser is considered.
NOZZLES WITH SHORT SUBSONIC CONTOURS AND A UNIFORM EXIT FLOW
409-421
10.1615/TsAGISciJ.v41.i4.40
Stanislav Viktorovich
Yagudin
Central Aerohydrodynamic Institute (TsAGI) 1, Zhukovsky str., Zhukovsky, 140180, Moscow region, Russia
nozzle
profiling
uniform inviscid flow
cut-off mode
characteristics
abruptly convergent contour
Presented in this article are the results of calculation and theoretical study of the problem of constructing the contour of a supersonic nozzle with a uniform exit inviscid gas flow, the contour of which is profiled from the endpoint of abruptly convergent subsonic area with the convergence angle θ = 90°. It is shown that there is a class of contours, in which the flow differs from the known concepts. The line of zero slope of the velocity vector θ = 0 consists of two different parts, partially or even completely located in front of the minimum section. The contour convergent areas, convex inward of flow, are streamlined without stagnation in front of the minimum sections.
DIFFUSERS OF GAS-DYNAMIC LASERS: WAYS TO IMPROVE
423-435
10.1615/TsAGISciJ.v41.i4.50
I. Yu.
Vasiliev
Central Institute of Aviation Motors, 2 Aviamotornaya St., Moscow, 111116, Russia
N. N.
Zakharov
Central Institute of Aviation Motors, 2 Aviamotornaya St., Moscow, 111116, Russia
A. N.
Kutuzova
Central Institute of Aviation Motors, 2 Aviamotornaya St., Moscow, 111116, Russia
supersonic diffuser
supersonic vaned diffuser
supersonic three dimensional diffuser
supersonic combined diffuser
gas-dynamic laser (GDL)
gas-dynamic start of GDL
diffuser stall
boundary-layer separation
three-dimensional interaction of
The analysis of features of gas-dynamic laser diffusers has been carried out. This analysis enables the definition of ways of to improve their starting and operating characteristics. Several original designs of effective multichannel diffusers are proposed, as well as the design of a gas-dynamic laser (GDL) flow passage containing a combined three-dimensional diffuser with tangential gas injection in the extreme channels and unsealed quick-acting doors in the optical section. The results of numerous model and full-scale tests of GDL with two- and three-dimensional diffusers are presented, and the comparison of their gas-dynamic characteristics is given.
VORTEX FLOWS OF A MICROPOLAR FLUID
437-449
10.1615/TsAGISciJ.v41.i4.60
Murad Abramovich
Brutyan
Central Aerohydrodynamic Institute (TsAGI), 1 Zhukovsky Str., Zhukovsky 140180, Russia
Vladimir Efimovich
Kovalev
Central Aerohydrodynamic Institute (TsAGI) 1, Zhukovsky str., Zhukovsky, 140180, Moscow region, Russia
non-Newtonian mechanics
micropolar fluid
vortex flows
exact solutions
Solutions describing vortex flows in the scope of equations of the micropolar fluid theory are found. These solutions are similar to well-known exact solutions of Oseen and Burgers for a classical Newtonian fluid. It is shown that the Oseen problem of diffusion of a straight vortex line in a micropolar fluid is not self-similar and has no exact solution. Unlike the Oseen problem, the solution of the Burgers problem of a stationary vortex in a micropolar fluid can be reduced to the solution of an ordinary differential equation system. For both problems, integral invariants are defined and a numerical solution is provided.
OPTIMIZATION OF ARRANGEMENT OF PRESSURE GAGES USING A SIMULATION MODEL OF LOCAL FIELDS OF GAS-DYNAMIC PARAMETERS
451-471
10.1615/TsAGISciJ.v41.i4.70
Nikolay Alekseevich
Zlenko
Central Aerohydrodynamic Institute (TsAGI) 1, Zhukovsky str., Zhukovsky, 140180, Moscow region, Russia
Vladimir Yur'evich
Podaruev
Central Aerohydrodynamic Institute (TsAGI) 1, Zhukovsky str., Zhukovsky, 140180, Moscow region, Russia
simulation model
CFD
regression analysis
pressure gages
Optimization of arrangement of pressure gages on an airplane nose is examined. An optimization problem algorithm is suggested. The choice of pressure gage positions and their calibration is made using results of parametric calculations of local fields of gas-dynamic parameters submitted as a simulation model.
SIMULATION OF AIRCRAFT ABRUPT RESPONSE IN DIRECTIONAL CONTROL
471-480
10.1615/TsAGISciJ.v41.i4.80
Pavel Anatolievich
Desyatnik
Central Aerohydrodynamic Institute (TsAGI), 1 Zhukovsky str., Zhukovsky 140180, Moscow region, Russia
aircraft handling qualities (HQs)
abrupt response (AR)
flight simulator
motion system drive algorithms
directional control
Considered are the problems of on-ground, motion-on simulation of specific forces and angular accelerations arising from aircraft abrupt response (AR) to pilot activity with regard to directional control. A method to simulate specific forces and angular accelerations is developed to predict the AR phenomenon at the first stages of aircraft development. Special attention was paid to the selection of motion system drive algorithms and their parameters with regard to directional AR reproduction. The motion system drive algorithm parameters were selected for different piloting tasks.
TECHNIQUE OF NUMERICAL EXPERIMENTS IN DESIGN CALCULATIONS OF HELICOPTER MECHANICAL SYSTEMS
481-504
10.1615/TsAGISciJ.v41.i4.90
Evgueniy Vladimirivich
Kasumov
Kazan State Technical University (KSTU), 10, K. Marx St., Kazan, Tatarstan 420111, Russia
Alexander I.
Golovanov
Kazan Federal University, 18 Kremlyovskaya St., Kazan 420008, Republic of Tatarstan, Russia
Vladimir Alekseevich
Shuvalov
Kazan Helicopters, 14 Tetsevskaya St., Kazan, Tatarstan, 420085, Russian
Federation
numerical experiment
mathematical model
design
helicopter
composite
composite material
mechanical system
kinematics
power analysis
finite-element method
deformation
stresses
Russian Federation methods of design calculation of mechanical systems are considered in the present paper. The technique suggested is based on the union of several groups of numerical simulation problems while solving problems related to statics and mechanical system motion under the influence of external forces. Analyses of structures made of composite materials and of light rotorcraft control system mechanisms are given as examples. Possibilities of the application of nonlinear problem solutions at the early stages of aircraft design are considered. Construction of solution algorithms of design problems is based on the mixed application of calculation software of Russian and foreign development.