scholarly journals ОСОБЛИВОСТІ ЗАБЕЗПЕЧЕННЯ АЕРОДИНАМІЧНИХ ХАРАКТЕРИСТИК РЕГІОНАЛЬНОГО ПАСАЖИРСЬКОГО ЛІТАКА

2019 ◽  
pp. 106-133
Author(s):  
Олександр Дмитрович Донець ◽  
Володимир Олександрович Кудрявцев
Keyword(s):  
High Speed ◽  
Research Work ◽  
Flight Dynamics ◽  
Aerodynamic Characteristics ◽  
Static Stability ◽  
Control Mode ◽  
Aviation Industry ◽  
Maximum Speed ◽  
Flight Tests ◽  
Aerodynamic Configuration

Principal results of the computational and research work performed during development of a regional passenger aircraft to ensure its aerodynamic characteristics are given. When creating the An-148-100/An-158 family of aircraft, such level of the aircraft aerodynamic perfection was achieved, which ensured fulfillment of the specified requirements for their flight performance – maximum speed, cruising flight altitude and flight range with different payloads. The developed aerodynamic configuration made it possible to create a family of regional passenger high-wing planes with a flight speed of up to 870 km/h (true speed) (M = 0.8), which have no analogues in the world aviation industry. Developed for the An-148-100 / An- 158 aircraft, supercritical profiles of the new generation with a large maximum relative thickness formed the basis of the aerodynamic configuration of a high-speed  wing with moderate sweep. The aircraft lift-to-drag ratio in cruise flight is Kcruise = 15.8, which corresponds to the worldwide values. Developed aerodynamic configuration of the wing high-lift devices provides high bearing properties of the wing during take-off and landing stages, which allows to fully meet the requirements for the runway required length of the base airfields Lrun = 1485...1950 m. Developed algorithms are implemented in the electric remote control system and provide necessary standard characteristics of stability, controllability and flight dynamics in the main control mode. Selected margins of the aircraft’s own static stability and effectiveness of its controls ensure safe completion of the flight in standby control mode. The certification flight tests of the An-148-100/An-158 airplanes confirmed full compliance of their take-off and landing performance, as well as the stability, controllability and flight dynamics characteristics with the requirements of the Certification basis in both standard and in failure situations tested in flight tests. Necessary and sufficient amount of experimental work was conducted in the lowspeed  and high-speed wind tunnels of the ANTONOV SC and TsAGI to verify the aerodynamic and spin characteristics of the An-148-100/An-158 airplane models, which improved the aerodynamic configuration of the aircraft and its individual units and allowed to apply the work results in calculation of aircraft strength, as well as for development of their systems.

STATIC STABILITY OF AERODYNAMICALLY SUPPORTED PLATFORMS MOVING ABOVE WATER

2021 ◽  
Vol 153 (A3) ◽  
Author(s):  
K I Matveev
Keyword(s):  
High Speed ◽  
Stability Margin ◽  
Ground Effect ◽  
Aerodynamic Characteristics ◽  
Static Stability ◽  
Underlying Surface ◽  
Geometrical Parameters ◽  
Marine Vehicles ◽  
Effect Theory ◽  
Rigid Plane

The motion stability is the most important problem of high-speed marine vehicles that utilize aerodynamic support. A simplified analysis and calculations of longitudinal static stability of several basic platforms moving above water are carried out in this study. The analysis is based on the extreme ground effect theory and the assumption of hydrostatic deformations of the water surface. Effects of the underlying surface type, Froude number, and several geometrical parameters on main aerodynamic characteristics, including the static stability margin, are presented. If the underlying surface is water instead of a rigid plane, the static stability worsens for platforms with flat or S-shaped lower surfaces, but it slightly improves for a horizontal platform with a flap. The static stability margin remains positive for S-shaped profiles at sufficiently low Froude numbers, while it is negative for other configurations.

scholarly journals Aerodynamic Characteristics Analysis and External Trajectory Simulation of High-speed Cross-media Water Entry Projectile

2021 ◽  
Vol 2079 (1) ◽  
pp. 012023
Author(s):  
Xu-Tuo Ding ◽  
Shi-Ji Li ◽  
Song-Jiang Peng ◽  
Jin Wei
Keyword(s):  
High Speed ◽  
Initial Conditions ◽  
Aerodynamic Characteristics ◽  
Static Stability ◽  
Water Entry ◽  
Aerodynamic Coefficients ◽  
Cross Media ◽  
Characteristics Analysis ◽  
The Stability ◽  
Trajectory Equation

Abstract The aerodynamic characteristics of a water entry projectile is studied. The aerodynamic coefficients at different Mach numbers and different attack angles are given through CFD numerical simulation, and the stability analysis is carried out. The results show that the projectile with the current shape meets the static stability requirements. Based on the aerodynamic coefficients obtained, the projectile flight trajectory equation is established to obtain the trajectory at different emissive angles. Finally, the trajectory parameters with the range of 5 km were used as the initial conditions for the simulation of high-speed water entry projectile, and the process of projectile entry with small angle was simulated. The simulation results show that the projectile sails smoothly when entering the water, the trajectory is straight, there is no ricochet phenomenon, which has a good water entry stability.

scholarly journals Performance Enhancement by Wing Sweep for High-Speed Dynamic Soaring

Aerospace ◽  
2021 ◽  
Vol 8 (8) ◽  
pp. 229
Author(s):  
Gottfried Sachs ◽  
Benedikt Grüter ◽  
Haichao Hong
Keyword(s):  
High Speed ◽  
Degrees Of Freedom ◽  
Performance Enhancement ◽  
Aerodynamic Characteristics ◽  
Progressive Increase ◽  
Maximum Speed ◽  
Horizontal Shear ◽  
Dynamic Soaring ◽  
Speed Performance ◽  
Wing Sweep

Dynamic soaring is a flight mode that uniquely enables high speeds without an engine. This is possible in a horizontal shear wind that comprises a thin layer and a large wind speed. It is shown that the speeds reachable by modern gliders approach the upper subsonic Mach number region where compressibility effects become significant, with the result that the compressibility-related drag rise yields a limitation for the achievable maximum speed. To overcome this limitation, wing sweep is considered an appropriate means. The effect of wing sweep on the relevant aerodynamic characteristics for glider type wings is addressed. A 3-degrees-of-freedom dynamics model and an energy-based model of the vehicle are developed in order to solve the maximum-speed problem with regard to the effect of the compressibility-related drag rise. Analytic solutions are derived so that generally valid results are achieved concerning the effects of wing sweep on the speed performance. Thus, it is shown that the maximum speed achievable with swept wing configurations can be increased. The improvement is small for sweep angles up to around 15 deg and shows a progressive increase thereafter. As a result, wing sweep has potential for enhancing the maximum-speed performance in high-speed dynamic soaring.

Cessna Citation X simulation turbofan modelling: identification and identified model validation using simulated flight tests

2019 ◽  
Vol 123 (1262) ◽  
pp. 433-463 ◽  
Author(s):  
Ruxandra Mihaela Botez ◽  
Paul-Alexandre Bardela ◽  
Thomas Bournisien
Keyword(s):  
Dynamic Model ◽  
Flight Dynamics ◽  
Flight Test ◽  
Federal Aviation Administration ◽  
Aviation Industry ◽  
System Response ◽  
Model Parameters ◽  
Flight Tests ◽  
Proposed Model ◽  
Research Aircraft

ABSTRACTThe aviation industry relies on accurate models. These models are used to predict an aircraft system’s outputs, and thus allow an understanding of the parameters involved, which could lead to system improvements. This study focuses on the engine modelling of an aircraft, and on its experimental validation using the Cessna Citation X Research Aircraft Simulator designed by CAE Inc., equipped with a level D Flight Dynamics toolbox. Level D is the highest rank attributed by the Federal Aviation Administration FAA certification authorities for flight dynamics. The proposed model aims to predict the thrust and the fuel consumption for various altitudes, Mach numbers and throttle lever angles (TLA). Different generic static models, which correspond to their steady state, from the literature, were used in this study; however, most of them were validated under restricted hypotheses. An optimisation algorithm was used in order to tune the static model parameters with the set of identification flight test data. Another set of data was then used in order to validate the identified model. Furthermore, a dynamic model corresponding to the transient operations was identified. TLA steps, impulses and ramp perturbations were performed in order to identify the system response, and to validate system dynamic model with other flight tests than the identification tests.

scholarly journals Problems of ensuring the acceleration dynamics of aircraft during track tests at a speed of 1600 m/s

2020 ◽  
Vol 12 (S) ◽  
pp. 33-42
Author(s):  
Sergey A. ASTAKHOV ◽  
Vasilii I. BIRIUKOV
Keyword(s):  
Test Object ◽  
High Speed ◽  
Variable Mass ◽  
Aerodynamic Characteristics ◽  
Maximum Speed ◽  
Rocket Engines ◽  
Rail Track ◽  
Hypersonic Aircraft ◽  
Engine Thrust ◽  
Upper Stage

The article discusses the problems that arise when creating new models of supersonic and hypersonic aircraft, which can be solved by model high-speed ground track tests. Mathematical modelling of the aerodynamic characteristics of an aircraft (test object) placed on a rail carriage and accelerated by the solid fuel rocket engines is performed. The numerical method solves the problem of the motion of a body of variable mass along a rail track. To determine the required length of the rail track, a mathematical model of the ballistic characteristics of the upper stage of the rocket carriage was compiled, calculations were made, and the influence of various factors on achieving the maximum speed of the test object was analysed. An analysis is made of the influence of the total mass of the carriage with the load and engine thrust on the possibility of accelerating the test object to the Mach speed (4-5).

Updated Efficient Area -Carry Select Adder for Low Complexity D LATCH Configuration by disease identification in brain tumor hyper spectral image

2019 ◽  
Vol 14 ◽  
Author(s):  
Teresa V.V ◽  
Anand. B
Keyword(s):  
Research Work ◽  
Low Complexity ◽  
Propagation Delay ◽  
Maximum Speed ◽  
Hyper Spectral ◽  
Ripple Carry Adder ◽  
Minimum Power Consumption ◽  
Carry Select Adder ◽  
The Look ◽  
Propagation Result

Objective: In this research work presents an efficient way Carry Select Adder (CSLA) performance and estimation. The CSLA is utilized in several system to mitigate the issue of carry propagation delay that is happens by severally generating various carries and to get the sum, select a carry because of the uses of various pairs of RCA to provide the sum of the partial section also carry by consisting carry input but the CSLA isn't time economical, then by the multiplexers extreme total and carry is chosen in the selected section. Methodology: The fundamental plan of this work is to attain maximum speed and minimum power consumption by using Binary to Excess-1. Convertor rather than RCA within the regular CSLA. Here RCA denotes the Ripple Carry Adder section. At the span to more cut back the facility consumption, a method of CSLA with D LATCH is implemented during this research work. The look of Updated Efficient Area -Carry Select Adder (UEA-CSLA) is evaluated and intended in XILINX ISE design suite 14. 5 tools. This VLSI arrangement is utilized in picture preparing application by concluding the cerebrum tumor discovery. Conclusion: In this study, medicinal pictures estimation, investigation districts in the multi phantom picture isn't that much proficient to defeat this disadvantage here utilized hyper spectral picture method is presented a sifting procedure in VLSI innovation restriction of cerebrum tumor is performed Updated Efficient Area - Carry Select Adder propagation result dependent on Matrix Laboratory in the adaptation of R2018b.

scholarly journals Aerodynamics of inclined cylindrical bodies free-flying in a hypersonic flowfield

2021 ◽  
Vol 62 (9) ◽  
Author(s):  
Patrick M. Seltner ◽  
Sebastian Willems ◽  
Ali Gülhan ◽  
Eric C. Stern ◽  
Joseph M. Brock ◽  
...  
Keyword(s):  
High Speed ◽  
Degrees Of Freedom ◽  
Numerical Data ◽  
Static Stability ◽  
Free Flight ◽  
Aerodynamic Coefficients ◽  
Flow Topology ◽  
Motion Data ◽  
Continuous Rotation ◽  
German Aerospace

Abstract The influence of the flight attitude on aerodynamic coefficients and static stability of cylindrical bodies in hypersonic flows is of interest in understanding the re/entry of space debris, meteoroid fragments, launch-vehicle stages and other rotating objects. Experiments were therefore carried out in the hypersonic wind tunnel H2K at the German Aerospace Center (DLR) in Cologne. A free-flight technique was employed in H2K, which enables a continuous rotation of the cylinder without any sting interferences in a broad angular range from 0$$^{\circ }$$ ∘ to 90$$^{\circ }$$ ∘ . A high-speed stereo-tracking technique measured the model motion during free-flight and high-speed schlieren provided documentation of the flow topology. Aerodynamic coefficients were determined in careful post-processing, based on the measured 6-degrees-of-freedom (6DoF) motion data. Numerical simulations by NASA’s flow solvers Cart3D and US3D were performed for comparison purposes. As a result, the experimental and numerical data show a good agreement. The inclination of the cylinder strongly effects both the flowfield and aerodynamic loads. Experiments and simulations with concave cylinders showed marked difference in aerodynamic behavior due to the presence of a shock–shock interaction (SSI) near the middle of the model. Graphic abstract

scholarly journals Research on aerodynamic characteristics of two-stage axial micro air turbine spindle for small parts machining

2020 ◽  
Vol 12 (12) ◽  
pp. 168781402098437
Author(s):  
Liu Jiang ◽  
Guo Zhiping ◽  
Miao Shujing ◽  
He Xiangxin ◽  
Zhu Xinyu
Keyword(s):  
High Speed ◽  
Aerodynamic Characteristics ◽  
Maximum Efficiency ◽  
Two Stage ◽  
Output Torque ◽  
Air Turbine ◽  
Solid Foundation ◽  
Computational Fluid Dynamics Cfd ◽  
Micro Machine ◽  
Small Parts

In order to meet the requirements of output torque, efficiency and compact shape of micro-spindles for small parts machining, a two-stage axial micro air turbine spindle with an axial inlet and outlet is proposed. Based on the k-ω turbulence model of SST, the flow field and operation characteristics of the two-stage axial micro air turbine spindle were studied using computational fluid dynamics (CFD) combined with an experimental study. We obtained the air turbine spindle under different working conditions of the loss and torque characteristics. When the inlet pressure was 300 KPa, the output speed of the two-stage turbine was 100,000 rpm, 9% higher than that of a single-stage turbine output torque. The total torque reached 6.39 N·mm, and the maximum efficiency of the turbine and the spindle were 42.2% and 32.3%, respectively. Through the research on the innovative structure of the two-stage axial micro air turbine spindle, the overall performance of the principle prototype has been significantly improved and the problems of insufficient output torque and low working efficiency in high-speed micro-machining can be solved practically, which laid a solid foundation for improving the machining efficiency of small parts and reducing the size of micro machine tool.

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