Begell House Inc.
TsAGI Science Journal
TSAGI
1948-2590
49
1
2018
AIR HUMIDITY EFFECT ON FLOW PARAMETERS IN SUBSONIC AND TRANSONIC WIND TUNNELS
1-12
10.1615/TsAGISciJ.2018026783
Anton Roaldovich
Gorbushin
Central Aerohydrodynamic Institute (TsAGI) 1, Zhukovsky str., Zhukovsky, 140180, Moscow region, Russia
wind tunnel
flow parameters
air humidity
correction
Corrections for the effect of the specific humidity on the Mach number, flow velocity, Reynolds number, and dynamic pressure in subsonic and transonic wind tunnels in the absence of vapor condensation are derived. The correction significance is estimated based on the accuracy of total and static pressure measurements and on the drag coefficient error requirements. The humidity corrections to the dynamic pressure and to the Mach and Reynolds numbers are found to be negligible. The correction to the flow velocity turns out to be significant, reaching the maximum value of 0.4% at the natural level of humidity.
NUMERICAL INVESTIGATION ON THE INTERACTION OF A PAIR OF HOT OFF-DESIGN SUPERSONIC JETS WITH A JET BLAST DEFLECTOR
13-28
10.1615/TsAGISciJ.2018026782
Leonid Aleksandrovich
Bendersky
Central Institute of Aviation Motors (CIAM), 2 Aviamotornaya Str., Moscow, 111116 Russia
Dmitriy Aleksandrovich
Lyubimov
Central Institute of Aviation Motors (CIAM), 2 Aviamotornaya St., Moscow, 111116, Russia
Aleksandra Olegovna
Chestnykh
Central Institute of Aviation Motors (CIAM), 2 Aviamotornaya Str., Moscow,
111116, Russian Federation
RANS/ILES method
turbulent jets
pair of jets
off-design supersonic jets
free jets
airfield jets
jet interaction with the jet blast deflector
jets with a co-flow
The interaction of a pair of hot off-design jets from biconical supersonic nozzles is numerically investigated by the high-resolution RANS/ILES method. The distance between the jet axes is four nozzle exit diameters. To improve the computational accuracy, combined computations of the flows in the nozzles and in the jets escaping from these nozzles are performed. The computations are carried out for free jets with a co-flow and for airfield jets with a jet blast deflector. Distances where mixing layers interaction begins, where jets are merging and where the difference of flow characteristic between one jet and twin jets are observed were obtained. The influence of the pair of jets on the near acoustic field is considered. For airfield jets, the effects of the co-flow velocity and the distance from the nozzle exit to the jet deflector on the size and shape of dangerous areas in terms of temperature, pressure fluctuations, and axial velocity are detected. Generalizing dependencies are presented for evaluating the influence of these parameters on the typical sizes of the dangerous zones. The results of the simulations are compared with similar data for single jet impingement onto the jet deflector. Specific features of the effects of the co-flow velocity and the jet deflector position on pressure, temperature, and their fluctuations over the jet blast deflector height are found.
ON THE COMPRESSIBLE COUETTE FLOW
29-41
10.1615/TsAGISciJ.2018026781
Valerii Nikolaevich
Golubkin
Central Aerohydrodynamic Institute (TsAGI), 1, Zhukovsky Str., Zhukovsky,
Moscow Region, 140180, Russian Federation
Grigorii Borisovich
Sizykh
Moscow Institute of Physics and Technology (MIPT), 9 Institutskiy Per.,
Dolgoprudny, 141700, Moscow Region, Russia
viscous compressible flow
Couette flow
exact solutions of Navierâ€“Stokes equations
Sutherland formula
Two exact solutions of Navierâ€“Stokes equations for steady compressible gas flow are found when the viscosity coefficient is related to temperature by the Sutherland formula. The first solution describes the plane shear flow between parallel plates moving with different velocities (analog to the incompressible Couette flow). The second solution is related to the shear flow between coaxial cylinders moving along the common axis. In the solutions obtained, all gas-dynamic parameters are expressed
by elementary one-variable functions. The compressibility effects on shear stress as well as the velocity and temperature profiles are investigated, including their qualitatively different configurations.
ESTIMATION OF AERODYNAMIC FORCES AND MOMENTS DERIVATIVES WITH RESPECT TO THE ANGULAR VELOCITY COMPONENTS OF THE AIRCRAFT MODEL IN A WIDE RANGE OF ANGLES OF ATTACK
43-64
10.1615/TsAGISciJ.2018026786
Mikhail Alekseyevich
Golovkin
Central Aerohydrodynamic Institute (TsAGI), Zhukovsky St., 1, Zhukovsky,
Moscow Region, 140180, Russian Federation
Andrey Aleksandrovich
Efremov
Central Aerohydrodynamic Institute (TsAGI), 1, Zhukovsky Str., Zhukovsky,
Moscow Region, 140180, Russia
Miroslav Sergeevich
Makhnev
Central Aerohydrodynamic Institute (TsAGI), Zhukovsky St., 1, Zhukovsky,
Moscow Region, 140180, Russian Federation
aerodynamic forces and moments
angular velocity components
rotary derivatives
large angles of attack
subsonic wind tunnels
Elementary estimations of derivatives of aerodynamic forces and moments coefficients with respect to the angular velocity components are presented based on the experiments on a test bed performing the aircraft model rotation at a constant angular velocity collinear to the wind tunnel incoming flow velocity vector. Analytical and semiempirical relations are given for assessing the contribution of
individual elements of aircraft model to rotary derivatives. An example of determining the rotary derivatives at low flow velocities for passenger aircraft model at both small and large supercritical angles of attack is shown.
COMPARATIVE NOISE ESTIMATION METHOD FOR GAS TURBINE POWER PLANTS OF JET PLANES
65-75
10.1615/TsAGISciJ.2018026769
Vladimir Grigor'evich
Dmitriev
Central Aerohydrodynamic Institute (TsAGI), Zhukovsky, Moscow region, Russia
Valerii Fedorovich
Samokhin
Central Aerohydrodynamic Institute (TsAGI), 1 Zhukovsky Str., Zhukovsky, Moscow Region, 140180 Russia
noise of transport category airplanes
noise of power plants of jet planes
estimation of noise level of airplane power plants
A noise estimation method for comparison of gas turbine power plants of jet planes is described. The method is based on certified acoustic tests of jet planes with a configuration of engines on pylons under a wing. This approach allows us to choose a newly developed airplane from the existing fleet of those engines which, as a part of a power plant, can produce the least environmental noise levels at take-off in terms of EPNdB. The dependence of noise level of airplane power plants on the bypass ratio and take-off thrust of engines is considered. Three groups of power plants are determined based on the "bypass ratio" parameter. Within each group, the power plants with minimum noise level are presented. The approximation dependencies of minimum noise levels on the engine thrust for a twin-engine layout are found for each group of power plants. The excess of the least noise levels of modern power plants is determined relative to the minimum levels of noise reached to the present time. The minimum levels can be an estimation of acoustic perfection degree of the power plants in
the group.
INFLUENCE OF LATERAL CONTROL SYSTEM ON TRANSPORT AIRCRAFT SPIN
77-92
10.1615/TsAGISciJ.2018026767
Diana Aleksandrovna
Alieva
Central Aerohydrodynamic Institute (TsAGI), 1, Zhukovsky Str., Zhukovsky,
Moscow Region, 140180, Russian Federation
Maria Evguenievna
Sidoryuk
Central Aerohydrodynamic Institute (TsAGI), 1 Zhukovsky St., Zhukovsky, Moscow Region, 140180, Russia
Alexander Nikolaevich
Khrabrov
Central Aerohydrodynamic Institute (TsAGI), Zhukovsky str. 1, Zhukovsky, 140180, Russia
spin
nonlinear mathematical model of aerodynamics
dynamic experiment
parametric continuation technique
time-domain simulation
spin recovery
lateral control system
The influence of a lateral control system on transport aircraft spin is reported. Although the control system has small influence on spin parameters, it may increase spin susceptibility of aircraft at deflections of the control surfaces with high rates and values. In addition, it decreases the probability of spin recovery success.
VERIFICATION OF A COMPUTATIONAL DYNAMIC MODEL OF A LAUNCH VEHICLE STRUCTURE
93-103
10.1615/TsAGISciJ.2018026788
Aleksandr Georgievich
Bakhtin
Khrunichev State Research and Production Space Center, 18, Novozavodskaya St., 121087 Moscow, Russian Federation
Vasilii Aleksandrovich
Titov
Central Research Institute of Machine Building (TsNIIMash), 4 Pionerskaya Str.,
Korolev, Moscow Region, 141070, Russian Federation
launch vehicle
analysis of load conditions
variation of dynamic characteristics
dense atmosphere
transient processes
Problems of verifying launch vehicle (LV) models are investigated for analysis of the loads due to wind disturbances and the response of control units as well as variations of the structural dynamic characteristics as a consequence of intensive fuel consumption. The paper aims to discuss the problems of verifying LV structure models used for load analyses through demonstration of their reliability in describing the unsteady processes against the variations of the dynamic characteristics. Special attention is paid to evaluation of marginal load capacity in transient processes, taking into consideration possible scatterings with respect to the structural and aerodynamic parameters.