TsAGI Science Journal, Issue 5, Year 2013
CIRCULAR CYLINDER IN A TRANSONIC FLOW OF A PERFECT GAS
V. A. Bashkin, I. V. Egorov, I. V. Ezhov, & S. V. Utyuzhnikov
The transonic cross flow of a viscous perfect gas around a circular cylinder is numerically simulated using nonstationary two-dimensional flow models. The computations are fulfilled in a sufficiently wide range of similarity parameters: 0.8 ≤ M∞·≤ 1.3, 103·≤ Re ≤·106 (laminar flow), and 106 ·≤Re ≤ 107 (turbulent flow). A streamlined surface is considered to be either adiabatic or isothermic with the temperature factor Tw0 = 0.5 (cooled surface) and 1.5 (overheated surface). The impact of the variable factors on the flow structure and aerodynamic characteristics of a circular cylinder are discussed.
KEY WORDS: circular cylinder, transonic flow, dynamics of viscous perfect gas,numerical modeling
HEAT TRANSFER ON THE FRONT SURFACE OF A BLUNT BODY IN HYPERSONIC FLOW
V. Ya. Neiland & L. A. Sokolov
The problem of determining the heat flux at a stagnation point of a blunt-nosed cylinder in a hypersonic viscous gas flow at high Reynolds numbers is considered. Passages to limit of M∞→∞, Re∞→∞ and ε= ρ∞ /ρ1→0 are used to find asymptotic solutions to the Navier—Stokes equations.
KEY WORDS: Navier—Stokes equations, boundary layer, Newton theory, strong vortical interaction
DIAGNOSTICS AND NUMERICAL SIMULATION OF FLOWS IN HYPERSONIC SHORT-DURATION WIND TUNNELS
V. Ya. Borovoy, V. N. Brazhko, I. V. Egorov, E. G. Zaitsev, & A. S. Skuratov
Stagnation pressure fields and heat fluxes in two short-duration wind tunnels, UT-1M Ludwig-type shock wind tunnel (M = 6 and 8) and IT-2M hot-shot wind tunnel (M = 12 and 20) are studied experimentally and numerically. The sizes of the dynamic and thermal core flows generated by contoured and conical nozzles are determined. It is demonstrated that the flow quality in the UT-1M and IT-2M wind tunnels is sufficiently high for performing aerodynamic and thermal tests of various models. Numerical simulations of the flow in the wind tunnel nozzles and test sections ensure an adequate description of the pressure distributions and Mach number contours.
KEY WORDS: shock wind tunnel, hot-shot wind tunnel, dynamic core flow, thermal core flow, total pressure probe, heat flux, numerical simulation
EFFECT OF AIRFOIL SHAPE WAVINESS ON ITS AERODYNAMIC CHARACTERISTICS AT LOW SUBSONIC SPEEDS
M. A. Brutyan, N. A. Vladimirova, & A. V. Potapchik
The results of comparative numerical and experimental investigations of the aerodynamic characteristics of National Advisory Committee for Aeronautics (NACA) 0012 airfoil and modified NACA 0012m airfoil are provided. The modified airfoil differs from the original one in that its diffuser part, starting from the position of maximum thickness, is a wavy surface. The systematic calculations of the wave optimal parameters have been made by a computer code based on the panel method for airfoil subsonic flow calculation with viscous/inviscid interaction. A standard load experiment has been carried out in a wide range of incidence angles α =
KEY WORDS: airfoil flow, wavy surface, incidences above stall, aerodynamic characteristics
QUASI-ONE-DIMENSIONAL SEPARATION TYPE MODEL OF PSEUDO-SHOCK IN A DUCT
E. A. Meshcheryakov & V. V. Yashina
A quasi-one-dimensional separation model of pseudo-shock in constant-area ducts is developed as applies to inlet isolators (diffusers) of scramjet engines. Based on this model, closed analytical dependences for the distance of the upstream pressure propagation on the backpressure, inlet Mach number, and duct shape are obtained. Using the single empirical constant, which has a simple physical meaning, the solution satisfactory describes a wide range of test data on pseudo-shock lengths in the ducts of various shapes. The model generalization is proposed for deceleration flows in divergent diffusers, which are found in wide applications in aerodynamic research. Some principal features of such flows are analyzed.
KEY WORDS: ramjet engine, isolator, pseudo-shock, combustion chamber, flow throttling
SKIDDED HELICOPTER LANDING PERFORMANCE STUDY BASED ON THE RESULTS OF FLIGHT TESTS
S. A. Alimov, S. A. Mikhailov, D. V. Nedelko, S. V. Saltykov, & A. A. Usoltsev
The results of flight tests on the Kazan Ansat helicopter while landing in the autorotation regime are analyzed. Based on the analysis results, the effect of the aerodynamic forces created by the rotor on the helicopter dynamics during landing is studied.
KEY WORDS: helicopter, landing, autorotation, skid
ON A ONE ANALYTICAL SOLUTION METHOD FOR THE DYNAMIC LAMINAR BOUNDARY-LAYER PROBLEM IN A SELF-SIMILAR CASE
V. N. Laptinskii
A new approach to the analysis of the Falkner—Skan equation is proposed. The estimates and the algorithms of the analytical solution construction for this problem are presented.
KEY WORDS: Falkner—Skan equation, analytical solution
CRITERIA FOR EXTENSION OF UAS AIRWORTHINESS FOR TEST AND DEMONSTRATION FLIGHTS
B. S. Alyoshin, V. L. Sukhanov, V. M. Shibaev, & V. I. Gorodnichenko
The methodological basis and criteria for extension of the airworthiness of unmanned aerial systems (UASs) for test flights and demonstration flights are developed based on simulation of the risk factor function.
KEY WORDS: unmanned aerial vehicle (UAV), unmanned aerial system (UAS), test flight, demonstration flight
FUSELAGE STRUCTURAL LAYOUT INVESTIGATION OF ADVANCED WIDE-BODY AIRCRAFT
V. I. Biryuk, A. A. Navoev, & V. I. Chernousov
In aerodynamic configurations, where the fuselage width is significantly larger than the fuselage height, problems related to internal pressure loading arise. An elliptic fuselage is considered, in which different structural layouts (SLs) with vertical or horizontal elements of the fuselage structure are analyzed. The criteria for the choice of SL are the weight of the structure and the uniformity of displacements as a function of the internal pressure along the fuselage length.
KEY WORDS: structural layout, internal pressure, fastened passenger floor, fastened cargo floor, ceiling beam
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