Begell House Inc.
TsAGI Science Journal
TSAGI
1948-2590
42
1
2011
EXPERIMENTAL INVESTIGATION OF THE SUPERSONIC BOUNDARY LAYER STABILITY ON A SWEPT WING AT MACH NUMBER M = 2
1-12
10.1615/TsAGISciJ.v42.i1.10
Yu. G.
Ermolaev
Khristianovich Institute of Theoretical and Applied Mechanics, Institutskaya str. 4/1, Novosibirsk, 630090, Russia
A. D.
Kosinov
Khristianovich Institute of Theoretical and Applied Mechanics, Institutskaya str. 4/1, Novosibirsk, 630090, Russia
N. V.
Semionov
Khristianovich Institute of Theoretical and Applied Mechanics, Institutskaya str. 4/1, Novosibirsk, 630090, Russia
supersonic boundary layer
swept wing
transition
stability
The experimental data of the investigation of stability of a 3D supersonic boundary layer on a swept wing are presented. The experiments are performed on a swept-wing model with a lenticular airfoil, with a swept angle of the leading edge of 45 deg, and at Mach number M = 2. Development of natural disturbances on the model of a thin swept wing is studied in detail on the basis of measurements. The characteristic regions of disturbance development are obtained. The Reynolds number of the region of instability of secondary flow disturbances is experimentally determined. It is shown that the secondary instability of a cross flow plays the main role in a laminar flow transition in the supersonic boundary layer on the swept-wing model.
CIRCULAR CYLINDER IN THE TRANSONIC FLOWOF A VISCOUS PERFECT GAS
13-36
10.1615/TsAGISciJ.v42.i1.20
Ivan Valeryevich
Ezhov
Central Aerohydrodynamic Institute (TsAGI), Zhukovsky Str. 1, Zhukovsky, 140180, Russia
Vyacheslav Antonovich
Bashkin
Central Aerohydrodynamic Institute (TsAGI), Zhukovsky, Moscow region, Russia
viscous fluid dynamics
numerical computation
transonic flow
circular cylinder
The results of numerical integration of unsteady 2D Navier-Stokes equations applied to a circular cylinder in a steady transonic flow of viscous perfect gas are discussed. The calculations at Re = 105 were fulfilled in the range of Mach numbers M∞ from 0.8 to 1.3 for cylinders with heat-insulated and isothermal (temperature factor Tw0 = 0.5) surfaces. It is shown that at M∞ ≤ M* a periodical separation of vortices from a streamlined surface occurs, and the flow around the cylinder is unsteady. In case of M∞ > M*, the periodical separation of vortices from the streamlined surface disappears, and the general structure of flow field is close to symmetrical; in addition, there is a narrow region of flow near the symmetry plane in the near wake where the motion of gas is unsteady. According to the calculations, 0.9 ≤ M* ≤ 0.95 for a heat-insulated cylinder and 0.8 ≤ M* ≤ 0.9 for isothermal cylinder. The comparison of calculated and experimental data on the distributions of local pressure and friction drag coefficients along the surface of cylinder at various Mach numbers is carried out.
DRAG OF CONE NOSES IN A SUPERSONIC FLOW
37-46
10.1615/TsAGISciJ.v42.i1.30
V. V.
Kovalenko
Central Aerohydrodynamic Institute, 1, Zhukvsky Str., Zhukovsky, 140180, Moscow Region, Russia
Alexander N.
Kravtsov
Central Aerohydrodynamic Institute named after Prof. N.Ye. Zhukovsky (TsAGI)
Tatiana Yurievna
Melnichuk
Central Aerohydrodynamic Institute (TsAGI), Zhukovsky Str. 1, Zhukovsky, 140180, Russia
axisymmetric flow
cone semiapex angle
supersonic flows
wave drag
friction drag
Results of numerical investigation of a supersonic flow around sharp circular cones at zero angle of attack are presented. An analysis of total drag constituents of a cone, namely, a wave drag and friction drag depending on the cone semiapex angle is carried out. This analysis proves the presence of the minimum of total drag. Dependences of the cone semiapex angle with minimum drag on the Reynolds number Re are obtained within the range of the Mach numbers of the incident flow M∞ = 3−8.
FEATURES OF NUMERICAL MODELING OF A DIELECTRIC BARRIER DISCHARGE
47-69
10.1615/TsAGISciJ.v42.i1.40
Vladimir Vladimirovich
Skvortsov
Central Aerohydrodynamic Institute (TsAGI) 1, Zhukovsky str., Zhukovsky, 140180, Moscow region, Russia
Alexander Petrovich
Kuryachii
Central Aerohydrodynamic Institute (TsAGI) 1, Zhukovsky str., Zhukovsky, 140180, Moscow region
Dmitriy Anatolyevich
Rusyanov
Central Aerohydrodynamic Institute (TsAGI), Zhukovsky Str. 1, Zhukovsky, 140180, Russia
dielectric barrier discharge
numerical modeling
drift-diffusion approximation
adsorption
desorption
recombination
secondary ion-electron emission
volumetric force
Joule dissipation
The boundary problem describing the generation of dielectric barrier discharge in air near a surface of dielectric plate by means of spatial periodic system of exposed electrodes with applied external harmonic voltage is formulated in the framework of a two-dimensional statement. Demonstrated is the significance of taking into consideration such parameters as the finite thickness of the exposed electrodes, an existence of the Knudsen layer near the plate surface and the electrodes, the finite rates of desorption and recombination of charged particles on a dielectric surface, the strength of the electric field induced by superficial charge on a dielectric fat the calculation of the conduction current, the volumetric force acting on a gas from the discharge, and the heat release (Joule dissipation) in the discharge. Numerical investigation of an influence of some physical parameters on mentioned characteristics of barrier discharge is carried out.
FACILITY FOR INVESTIGATIONS OF TOTAL HEMISPHERICAL EMISSIVITY OF HEAT PROTECTION MATERIALS AND THERMAL CONTROL COATINGS
71-82
10.1615/TsAGISciJ.v42.i1.50
Oleg Dmitrievich
Tokarev
Central Aerohydrodynamic Institute (TsAGI), Zhukovsky Str. 1, Zhukovsky, 140180, Russia
Boris Viktorovich
Prusov
Central Aerohydrodynamic Institute (TsAGI), Russia
Leonid Yakovlevich
Paderin
Central Aerohydrodynamic Institute (TsAGI), Zhukovsky Str. 1, Zhukovsky, 140180, Russia
heat protection materials
thermal control coatings
total hemispherical emissivity
temperature
total radiant flux
This work is dedicated to an improvement of technique and modernization of experimental facility for the purpose of the maximum temperature level increase at investigations of total hemispherical emissivity of heat protection materials and thermal control coatings. Within the scope of the facility modernization a new heater based on modern high temperature materials and new measurement instruments for temperature and radiant heat flux measurements are developed. As a result of the conducted measures the maximum temperature level of samples under study is increased from 1500 up to 2000 K. A series of control tests are carried out. These tests verify the technique efficiency and operability of the modernized experimental facility in an extended temperature range.
DESCRIPTION OF MARKOVIAN PROCESS DYNAMICS IN AN EXTENDED SPACE OF VARIABLES
83-108
10.1615/TsAGISciJ.v42.i1.60
O. N.
Khatuntseva
Central Aerohydrodynamic Institute (TsAGI), Zhukovsky str. 1, Zhukovsky, 140180, Russia
Markovian processes
functions with discontinuities
probability density
stochastic va-riables
An extension of the space of variables at the description of stochastic processes enables a closed system of equations describing iterative mappings of an investigated parameter at different time scales of consideration of such systems to be obtained. Simultaneous solving of mathematical models, applied to description of deterministic processes in the space with additional stochastic variables, and equations, describing the iterative mapping of investigated parameter, is proposed for a description of physical systems in which stochastic processes are significant.
SYNTHESIS OF A SYNCHRONIZATION ALGORITHM FOR INTEGRATORS OF A DIGITAL REDUNDANT CONTROL SYSTEM
109-118
10.1615/TsAGISciJ.v42.i1.70
Sergey Georgievich
Bazhenov
Central Aerohydrodynamic Institute (TsAGI), Zhukovsky str. 1, Zhukovsky, Moscow region, 140180 Russia
digital control system
redundancy
asynchronous operation
control and monitoring channels
integrators
synchronization
Operational differences between integrators of a modern digital redundant control system are analyzed. An algorithm is proposed to synchronize integrators both between control and monitoring channels of a computer, and between computers of a digital redundant control system. Preliminary parameters of a synchronization algorithm are selected.
APPLICATION OF THE MODEL OF VARIABLE DENSITY AT EARLY STAGES OF WING DESIGN
119-133
10.1615/TsAGISciJ.v42.i1.80
V. A.
Komarov
S.P. Korolev Samara State Aerospace University, 34, Moscow Highway, Samara, 443086, Russia
A. V.
Boldyrev
S.P. Korolev Samara State Aerospace University, 34, Moscow Highway, Samara, 443086, Russia
finite element method
variable density model
constructive-power scheme
optimization methods
A technique of rational choice of the power scheme and weight pre-diction for the wing lifting surfaces using a special finite element model is proposed. The technique takes into account the wing deformations and requirements to the configuration stiffness. Numerical examples are given.