Begell House Inc.
TsAGI Science Journal
TSAGI
1948-2590
46
6
2015
NEW METHOD OF OPTICAL INVESTIGATIONS OF BOUNDARY LAYER STATE IN AERODYNAMIC EXPERIMENT
509-517
10.1615/TsAGISciJ.v46.i6.10
Murad Abramovich
Brutyan
Central Aerohydrodynamic Institute (TsAGI), 1 Zhukovsky Str., Zhukovsky 140180, Russia
Albert Vasilievich
Petrov
Central Aerohydrodynamic Institute (TsAGI) 1, Zhukovsky str., Zhukovsky, 140180, Moscow region
Aleksandr Vladimirovich
Potapchik
Central Aerohydrodynamic Institute (TsAGI), 1 Zhukovsky Str., Zhukovsky 140180, Russia
non-contact measurements
boundary layer
transition trips
aerodynamic experiment
The optical method of transonic flow investigation around airfoils is offered based on the effect of boundary layer state influence on light scattering effect of a parallel beam passing through it. Some examples of the new method practical application are given.
THE REFINED COLES' LAW OF THE WAKE
519-532
10.1615/TsAGISciJ.v46.i6.20
Vladimir Victorovich
Mikhailov
Central Aerohydrodynamic Institute (TsAGI), Zhukovsky str. 1, Zhukovsky, 140180, Russia
Nina Veniaminovna
Samoilova
Central Aerohydrodynamic Institute (TsAGI), Zhukovsky str. 1, Zhukovsky, 140180, Russia
turbulent boundary layer
the wake law
"half power law"
The Reynolds-average flow of incompressible fluid in a two-dimensional turbulent boundary layer is considered. The layer is supposed to be sufficiently thin up to the separation point, so that only the Reynolds' shear stress tangential to the body surface affects the layer. In other words, the flow considered is similar to the plane-parallel flow, when the "smooth" separation is realized. The new refined modification of Coles' function of the wake is proposed. This refined function approximates
well the mean-velocity profile and skin-friction coefficient. The formparameter H maximum value
equal to 3.89 is reached at the "smooth" separation regime. The derivation of the wake law is based
on the fundamental assumption of the one-parameter nature of the velocity defect profile, which is repeatedly confirmed experimentally. It is shown that the proposed wake function near separation section has a velocity profile zone where the well-known "half power law" is fulfilled. However, in the section of a "smooth" separation such a zone almost disappears. Results of this study are confirmed by the comparison with the experimental data.
METHOD OF OPTIMAL AERODYNAMIC DESIGN OF THE NACELLE FOR THE MAIN PROPULSION SYSTEM WITH A HIGH BYPASS RATIO
533-558
10.1615/TsAGISciJ.v46.i6.30
Nikolay Alekseevich
Zlenko
Central Aerohydrodynamic Institute (TsAGI) 1, Zhukovsky str., Zhukovsky, 140180, Moscow region, Russia
Sergey Vladimirovich
Mikhaylov
Central Aerohydrodynamic Institute (TsAGI) 1, Zhukovsky str., Zhukovsky, 140180, Moscow region, Russia
Andrey Aleksandrovich
Savelyev
Central Aerohydrodynamic Institute (TsAGI), 1 Zhukovsky St., Zhukovsky, Moscow Region, 140180 Russia
Andrey Vladimirovich
Shenkin
Central Aerohydrodynamic Institute (TsAGI), 1 Zhukovsky St., Zhukovsky, Moscow Region, 140180 Russia
optimization
aerodynamic design
computational fluid dynamics
nacelle
An algorithm of optimal aerodynamic design of the contour of the main propulsion system nacelle for a subsonic airliner, which is based on numerical methods used for solving the Reynolds-averaged Navier−Stokes equations, is proposed. The use of methods of conditional optimization of a multifactor function makes it possible to form an aerodynamically efficient nacelle contour under the condition of a large number of aerodynamic and structural constraints. The capabilities of the proposed technique are illustrated by results of optimization of the shape of an isolated nacelle of the main propulsion
system with a high bypass ratio designed for a mid-range passenger airliner.
NUMERICAL ANALYSIS OF SINGLE-EXPANSION RAMP NOZZLE PERFORMANCE IN SUPERSONIC FLOW
559-576
10.1615/TsAGISciJ.v46.i6.40
Anatoliy Pavlovich
Mazurov
Central Aerohydrodynamic Institute (TsAGI), Zhukovsky str. 1, Zhukovsky, 140180, Russia
single-expansion ramp nozzle
viscous gas
numerical method
nozzle impulse vector
nozzle thrust vector
An analysis of results of a numerical investigation of characteristics of a single-expansion ramp nozzle (SERN) in supersonic flow is presented. Computations were conducted on the basis of the three-dimensional Reynolds-averaged Navier−Stokes equations in thin-layer approximation. A differential k−ε turbulence model which accounts for wall influence was used to calculate the turbulent viscosity.
The results of the effect of a nozzle pressure ratio (NPR) and geometric parameters on the local and
integral characteristics of the SERN nozzle with a profiled contour are presented. The longitudinal
thrust coefficient varies non-monotonically, reaching a maximum at a certain NPR value from a considered range. The vertical component and the angle of the thrust vector have negative values and increase monotonically with increasing NPR. The nozzle impulse coefficients do not depend on the NPR. When the nozzle exit height increases the longitudinal thrust coefficient decreases or increases, reaching the maximum, in dependence on the nozzle length. The maximum of the longitudinal thrust
is reached at the thrust vector angle closed by zero. The vertical thrust coefficient and the thrust
vector angle decrease monotonically with increase of the nozzle exit height independence on the nozzle
length. Data on the effect of the nozzle exit height and nozzle length on the coefficients of the external
aerodynamic forces and moments are also presented.
METHOD OF COMPUTATIONS OF LOADS AT THE DESIGN OF ROTOR UNITS AND HELICOPTER CONTROL SYSTEM
577-590
10.1615/TsAGISciJ.v46.i6.50
Andrei Yurievich
Barinov
Mil Moscow Helicopter Plant, 26/1, Garshina st., Tomilino, Lyuberetsky District, Moscow Region, 140070 Russia
Nikolai Serafimovich
Pavlenko
Mil Moscow Helicopter Plant, 26/1, Garshina st., Tomilino, Lyuberetsky District, Moscow Region, 140070 Russia
rotor
hinge moment
oscillations
blade deformations
differential equations
A method allowing determination of the following parameters is developed, namely, aerodynamic rotor characteristics (thrust, longitudinal and transversal forces, torque at axle), the collective pitch angle to obtain the specified rotor thrust; the angles of cyclic pitch required to create the helicopter balance moments on the bush; the angle of attack of the helicopter rotor needed for specified speed flight; blade deformations in the flap plane, in the rotation plane; torsion deformations and corresponding to these deformations bending and hinge moments and their harmonic composition. The results of the computations of the hinge moments are presented. This method is developed for a rotor with blades elastic in the planes of thrust, rotation, and torsion, for hinge and rigid attaching of the blades in the base, and also for complex structures of the bush of modern semi-rigid and rigid rotors with elastic elements,
control cases, and elastomeric hydraulic dampers and tips with the sweep and with deflection downward.
THE STATIC PRESSURE INFLUENCE ON ELECTROPHYSICAL CHARACTERISTICS OF A DIELECTRIC BARRIER DISCHARGE
591-607
10.1615/TsAGISciJ.v46.i6.60
Marat Dzhaudatovich
Gamirullin
Central Aerohydrodynamic Institute (TsAGI), 1 Zhukovsky Str., Zhukovsky, Moscow Region, 140180 Russia
Vladimir Mikhailovich
Litvinov
Central Aerohydrodynamic Institute (TsAGI), Zhukovsky str. 1, Zhukovsky, Moscow Region, 140180 Russia
Tatiana Anatolyevna
Pimenova
Central Aerohydrodynamic Institute (TsAGI), Zhukovsky str. 1, Zhukovsky, Moscow Region, 140180 Russia
Igor Evgenievich
Rebrov
Institute of Electrophysics and Electroenergetics of the Russian Academy
of Sciences, 18 Dvortsovaya Emb., St. Petersburg, 191186 Russia
Aleksandr Aleksandrovich
Uspenskii
Central Aerohydrodynamic Institute (TsAGI), Zhukovsky str. 1, Zhukovsky, Moscow Region, 140180 Russia
Andrey Yuryevich
Urusov
Central Aerohydrodynamic Institute (TsAGI), 1 Zhukovsky Str., Zhukovsky,
Moscow Region, 140180, Russian Federation
dielectric barrier discharge
plasma actuator
total pressure probe
flow velocity
static pressure
volumetric force
electric power
energy efficiency
The results of experimental investigation of electro-physical characteristics of plasma actuators (the DBD actuators), intended for the boundary layer flow control by an excitation of a dielectric barrier discharge, are presented. The experiments were carried out at the static pressure change in a wide range from the atmospheric pressure to the low pressure, corresponding to the real flight conditions at heights 10-12 km. As the models of the actuators, the flat dielectric plates with the discharge electrodes located on the surface were used. The discharge excitation was implemented by a high-voltage impulse generator that formed the impulses of amplitude of 2-5 kV, of duration of 20–35 μ;s and with frequency
of 2.5-6.25 kHz. The consumption of electric power for the discharge maintenance as a function of pressure, of an incoming flow velocity, and of an operational regime of actuators (frequency and voltage amplitude) was determined. On the basis of integral momentum-transfer method with the use of the velocity profiles induced by the actuators, the evaluations of the volumetric force generated by the discharge were performed. The evaluations of energy efficiency of an actuator as a function of
pressure and the discharge parameters were done.
HYDROGEN INJECTION INTO A SUPERSONIC FLOWOF AIR IN A CHANNEL WITH RADIAL PYLONS
609-618
10.1615/TsAGISciJ.v46.i6.70
Dmitrii Pavlovich
Alekseev
Moscow State Industrial University, 16, Avtozavodskaya St., Moscow,
115280, Russia
Yurii Vladimirovich
Tunik
Institute of Mechanics (Lomonosov Moscow State University), Michurinskii av., 1, Moscow, 119192
mixing of gas flows
turbulence
viscosity
diffusion
hydrogen-air mixture
total pressure loss
pylon
Hydrogen injection into a supersonic flow of air through pylons radially oriented in an axisymmetric uniform section channel with an inner coaxial cylinder is considered. The injection parameter influence on the mixing intensity, total pressure, and quality of the forming hydrogen-air mixture is
studied. The investigations are fulfilled numerically on the basis of Reynolds-averaged Navier−Stokes equations for a turbulent flow of a multi-component viscous gas.