Begell House Inc.
TsAGI Science Journal
TSAGI
1948-2590
42
2
2011
FOR THE 100th ANNIVERSARY OF THE MSTISLAV V. KELDYSH'S BIRTH. THE BEGINNING OF CREATIVE WAYS: WORK AT TSAGI
135-140
10.1615/TsAGISciJ.v42.i2.10
Boris Sergeevich
Alyoshin
Central Aerohydrodynamic Institute (TsAGI), Zhukovsky Str. 1, Zhukovsky 140180, Russia
Work at TsAGI
ASYMPTOTIC SOLUTION OF THE PROBLEM OF A SUBSONIC GAS FLOW AROUND AN AIRFOIL WITH A LOCAL SUPERSONIC AREA FORMATION
141-149
10.1615/TsAGISciJ.v42.i2.20
Anatoliy Vasil'evich
Zubtsov
Central Aerohydrodynamic Institute (TsAGI) 1, Zhukovskystr., Zhukovsky, 140180, Moscow region, Russia
Georgiy Grigoryevich
Soudakov
Central Aerohydrodynamic Institute (TsAGI), Zhukovsky Str. 1, Zhukovsky 140180, Russia
airfoil
transonic flow
supersonic area
asymptotic solution
The problem of a transonic flow around an airfoil with a relative thickness of τ << 1 is considered. An asymptotic solution of this problem is obtained for the case of a local supersonic area formation on a smooth airfoil surface. A relative longitudinal dimension of the local supersonic area is proposed to be small, lx << 1. It is shown that in the case when the airfoil surface curvature in the vicinity of the supersonic area is continuous and has order O (τ), a transition of the supersonic flow to the subsonic flow occurs in a continuous way. It is also shown that the shock can arise on the smooth airfoil surface if M∞ − M∞ cr = O (τ2/3).
FLOW IN THE NEIGHBORHOOD OF THE BREAKPOINT OF THE LEADING EDGE THIN WING AT THE STRONG INTERACTION REGIME
151-167
10.1615/TsAGISciJ.v42.i2.30
Aleksey Vyacheslavovich
Ledovskiy
Central Aerohydrodynamic Institute (TsAGI), 1 Zhukovsky Str., Zhukovsky 140180, Russia
Georgiy Nikolaevich
Dudin
Central Aerohydrodynamic Institute (TsAGI), 1, Zhukovsky Str., Zhukovsky,
Moscow Region, 140180, Russian Federation
boundary layer
the wing
hypersonic flow
strong viscous-inviscid interaction
The spatial laminar boundary layer on a thin wing in the neighborhood of the breakpoint of the leading edge in hypersonic wrap is investigated in this paper. The regime of strong viscous-inviscid interaction is considered. Variables, allowing for the reduction of the boundary value problem to a two-dimensional, and on the front edge, to systems of common differential equations are defined. To determine the induced pressure, the second-order differential equation is used. A numerical solution of the problem is obtained. The results of parametric calculations of the wing shape influence in plan, temperature factor, adiabatic exponent, and Prandtl number on the flow characteristics in the spatial boundary layer are presented. The size of the subsonic flow in a laminar boundary layer is also defined.
PECULIARITIES OF DRAG OF THE REVOLUTION POWER-LAW BODIES
169-177
10.1615/TsAGISciJ.v42.i2.40
Alexander N.
Kravtsov
Central Aerohydrodynamic Institute named after Prof. N.Ye. Zhukovsky (TsAGI)
power-law bodies of revolution
supersonic flows
wave drag
friction drag
The results of numerical investigation of the drag of the revolution power-law bodies at supersonic free stream velocities are presented in this paper. Qualitative peculiarities of supersonic overflow, associated with the drag of optimal axisymmetric aerodynamic configurations, are considered. The peculiarities of the rise of the minimum of the drag coefficient function of the generatrix exponent are revealed in the class of power-law revolution bodies at supersonic overflow. It is shown that the wave drag coefficient along the length of an optimal power-law revolution body increases according to the function, which is close to be linear.
AERODYNAMIC CALCULATION METHOD OF THE MAIN ROTOR TAKING INTO ACCOUNT DIFFUSION OF FREE VORTICES FOR SMALL FLIGHT SPEEDS
179-203
10.1615/TsAGISciJ.v42.i2.50
Valentina Michailovna
Scheglova
Central Aerohydrodynamic Institute (TsAGI) 1, Zhukovsky str., Zhukovsky, 140180, Moscow region, Russia
induced velocities
helicopter
main rotor
blade
vortex wake
sheet
vortex’s thickness
diffusion
The object of investigation is a five-blade model of a main helicopter rotor. The work purpose is to find an acceptable mathematical modeling of the nonlinear diffusion vortex wake of the main helicopter rotor and loadings on the main rotor's blades connected with the induction of the wake. The increase of vortices descending from the blade's cross dimension during the diffusion process, along with their circulation decrease, was taken into account. In the investigation in question, these two variables are interconnected. The distribution of vorticity in diffusing vortex lines with the axis moving in the velocity field given was considered. Formulas for the calculation of induced velocities caused by vortex lines were derived. The velocities from the finite cross section volumetric vortex tubes concerned were reduced to the linear integral about the tube axis of expression, representing a generalization of Biot-Savart law. The problems of vortex diffusion influence on aerodynamic loadings, blade-span instant induced velocities, and average induced velocities at points of free diffusion vortices wake in working conditions in a system of joint definition of loadings and induced velocities were numerically investigated. The calculation series for a blade of a five-blade model main rotor on determination of vortex wake shape and induced velocities on a disk, taking into account flight speed diffusion corresponding to μ; = 0.15, was fulfilled. In this work, the attempt was made to determine the thickness of the vortices descending from the blade based on the thickness of the boundary layer δ, with a further increasing value of δ depending on time. Calculations were compared using this method with experiments both in the location of the vortex plane and in determining the values of average induced velocities in the wake behind the rotor.
FLOW AROUND A SOLID BODY OF THE HEATED SUPERSONIC GAS-DISPERSED JET WITH ACCOUNT OF THE ROTATION OF THE REJECTED PARTICLES
205-225
10.1615/TsAGISciJ.v42.i2.60
Galina Vasilievna
Molleson
Central Aerohydrodynamic Institute, Zhukovsky, Moscow region, Russia, 140180
Al'bert Leonidovich
Stasenko
Central Aerohydrodynamic Institute, Zhukovsky, Moscow region, Russia, 140180
gas-dynamic acceleration of microparticles
heat radiation
restoring coefficients of the velocity components
shock layer
rotation of the rebounded particles
flow densities of the mass
momentum
energy of the particles
A physico-mathematical model of a particle-carrying gas interaction taking into consideration the Magnus force, experimental data on the mutual influence of the particle linear motion and spinning, the finite time of particle heating, and the cutoff of its heat radiation spectrum, is developed. The carrying gas dynamics is described within the framework of the Euler approach, with heat radiation of the gas and solid body being neglected, as well as erosion of this body. A wide range of particle dimensions is investigated numerically, in which various regimes of the particle-body surface interaction are implemented (adhesion, rebound, absolutely inelastic collision). The influence of the particle self-radiation on their heat exchange is evaluated. These algorithms allow calculation of the mass, momentum, and energy flow densities carried by the particles upon an axisymmetric body surface that is streamlined, in particular, by a two-phase jet.
MODELING OF DIELECTRIC BARRIER DISCHARGE ACTUATORS AT VARIOUS GAS PRESSURES AND ESTIMATION OF THEIR INFLUENCE ON SHEAR FLOWS
227-243
10.1615/TsAGISciJ.v42.i2.70
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
Vladimir Vladimirovich
Skvortsov
Central Aerohydrodynamic Institute (TsAGI) 1, Zhukovsky str., Zhukovsky, 140180, Moscow region, Russia
dielectric barrier discharge
drift-diffusion approximation
volumetric force
heat release
DBD actuator
Navier-Stokes equations
Poiseuille and Couette flows
Numerical research of the gas pressure influence on a conduction current in a dielectric barrier discharge (DBD), the average volumetric force acting on gas from the discharge, and the power of heat release in the discharge is carried out for aerodynamic applications. The calculations are implemented with use of the earlier proposed boundary problem about the DBD generation near a flat dielectric plate. This problem statement takes into account such factors as the finite thickness of the exposed electrode, finite rates of desorption and the recombination of charged particles on the dielectric surface, and the electric field induced by a superficial charge. Represented are the results of numerical modeling of the incompressible Poiseuille and Couette flows under the time-averaged transverse force impact of DBD actuators placed along the main flow. The possibility of significant influence of an additional transfer of the main flow momentum due to the cross-flow (induced by actuators) on the structure and the characteristics of the considered shear flows is demonstrated.
STABILITY EVALUATION OF AN AIRPLANE WITH A DIGITAL MULTIRATE CONTROL SYSTEM IN A LATERAL MOTION
245-258
10.1615/TsAGISciJ.v42.i2.80
Sergey Georgievich
Bazhenov
Central Aerohydrodynamic Institute (TsAGI), Zhukovsky str. 1, Zhukovsky, Moscow region, 140180 Russia
stability
airplane
lateral motion
digital control system
multirate sampling
MIMO system
decomposition
Stability margins of an airplane with a control system are analyzed for lateral motion. Different architectures of the control system are considered, namely, the analog system, the digital single-rate control system (single-channel and triplex-channel cases), and the digital multirate control system (single-channel and triplex-channel cases). The effect of interchannel data equalization on the stability margins of the closed-loop system "airplane-Fly-By-Wire (FBW) system" is analyzed. While analyzing the stability of a multiloop system, its decomposition to internal contours is used. The stability analysis of a triplex system includes cases of a failed sensor of backloop signal in one channel.
ALGORITHMS FOR STRUCTURAL TOPOLOGY OPTIMIZATION
259-274
10.1615/TsAGISciJ.v42.i2.90
V. V.
Sysoeva
Mil Moscow Helicopter Plant, Garshina St. 26/1, Tomilino Village, Moscow region, Russia
Vasilii Vasil'evich
Chedrik
Central Aerohydrodynamic Institute (TsAGI), Zhukovsky St. 1, Zhukovsky 140180, Russia
topology optimization
optimality criteria
fully-stressed design
many load cases
Two heuristic methods of structure topology optimization are presented. They are based on the application of the fully-stressed design criterion, used in practice to determine the structural rational parameters taking into account the strength constraints. Peculiarities of the developed algorithms are considered, and a comparative analysis of the optimization results with the known solutions by other algorithms is fulfilled.