Study of Aerodynamic Characteristics of Cylindrical Bodies in a Supersonic Flow

2011 ◽  
Vol 6 (4) ◽  
pp. 16-24
Author(s):  
Vladimir Kornilov ◽  
Vladimir Lysenko
Keyword(s):  
Mach Number ◽  
Aspect Ratio ◽  
Stokes Equations ◽  
Aerodynamic Force ◽  
Angle Of Attack ◽  
Aerodynamic Characteristics ◽  
Circular Cylinders ◽  
Coordinate Systems ◽  
Flow Parameters ◽  
Cylinder Drag

Analysis of experimental and computational aerodynamic characteristics of smooth flat-face circular cylinders with the aspect ratio of 0,6 to 12,0 is given. Studies have been carried out at Mach number М= 4 for the angle of attack range  = 0900 . Effect of the cylinder aspect ratio and angle of attack on aerodynamic force coefficients in wind axes- and body axes coordinate systems is shown. A number of distinctive peculiarities in the behavior of the cylinder drag coefficient are revealed. The results obtained are presented in a form of a unique generalized dependence. The computation of some flow parameters around a cylinder has been performed within the Navie – Stokes equations, results of which are compared with the flow visualization data

scholarly journals РОЗРАХУНОК АЕРОДИНАМІЧНИХ ХАРАКТЕРИСТИК НАДЗВУКОВИХ ОПЕРЕНИХ ОСЕСИМЕТРИЧНИХ ТІЛ ОБЕРТАННЯ

2019 ◽  
pp. 4-17
Author(s):  
Олександр Миколайович Шийко ◽  
Анатолій Михайлович Павлюченко ◽  
Андрій Вікторович Скорик ◽  
Олексій Анатолійович Обухов ◽  
Ігор Володимирович Коплик
Keyword(s):  
Numerical Solution ◽  
Stokes Equations ◽  
Aerodynamic Force ◽  
Angle Of Attack ◽  
Aerodynamic Characteristics ◽  
Navier Stokes ◽  
Aerodynamic Coefficients ◽  
Navier Stokes Equations ◽  
Friction Resistance ◽  
Ansys Cfx

The subject of research in the article is the aerodynamic forces arising from the flight of supersonic feathered rotation bodies such as unguided rockets. The aim of the work is to develop a method for calculating the aerodynamic coefficients of the resultant forces and moments of supersonic feathered bodies of revolution such as unguided missiles when flown around at an angle of attack with pre-, trans- and supersonic speeds according to drawings of their external contours. Tasks: using modern software systems and flight experiments, develop a method for calculating the distribution of normal and tangential stresses over the surface of a supersonic feathered body of rotation, their equivalent and aerodynamic coefficients at up-, trans- and supersonic flow velocities at an angle of attack. The applied methods are the numerical solution of the Navier-Stokes equations, the use of two-parameter differential models of near-wall turbulent viscosity, verification of the methodology by comparing the results of calculations with the data of flight experiments and known data on the aerodynamic resistance of the object of research. The following results were obtained. Based on the numerical solution of the Navier-Stokes equations in the ANSYS CFX software package using the γ-ReΘt SST–model of Menter’s near-wall turbulence, a method is developed for calculating the aerodynamic characteristics of supersonic axially symmetric rotation bodies of uncontrollable missiles according to drawings of the external contours in the presence of a counter-flow angle. Using the developed technique it is possible to calculate the aerodynamic coefficients of friction resistance, pressure resistance and bottom resistance at sub-, trans- and supersonic speeds. Characteristics include the coefficients of the longitudinal aerodynamic force, transverse aerodynamic force, aerodynamic stabilizing moment and the coordinate of the center of pressure of the feathered body of rotation. For the calculations, were applied the external contours of the unguided missile M–21OФ. Calculations were performed for the counter-flow Mach numbers within0,1 £ M∞ £ 2,5. The aerodynamic coefficients were calculated as functions of the Mach number M∞. In order to determine the Reynolds number of the beginning of the laminar-turbulent transition in the boundary layer for this type of aircraft the characteristics of the friction resistance were calculated and compared with the flight data for two samples of research aerophysical complexes. Conclusions. The scientific novelty of the results is as follows: a pilot test was created and involved the results of flight experiments on Reynolds numbers of the start of a laminar-turbulent transition in the boundary layers of a method for calculating the aerodynamic drag coefficients of supersonic axially rotated bodies of rotation like uncontrollable missiles according to the drawings of their external contours during turning angle of attack based on the numerical solution of the Reynolds-averaged Navier-Stokes equations in the framework of the programme product ANSYS CFX using γ-ReΘt SST–Menter turbulence model. Verification of the calculation results was carried out on the basis of their comparison with the known values of the aerodynamic characteristics of the object of research with the axisymmetric flow.

scholarly journals 2D Numerical Simulation Study of Airfoil Performance

2021 ◽  
Author(s):  
Nasser Shelil
Keyword(s):  
Experimental Data ◽  
Wind Tunnel ◽  
Air Temperature ◽  
Wind Turbines ◽  
Aerodynamic Force ◽  
Angle Of Attack ◽  
Turbulence Models ◽  
Aerodynamic Characteristics ◽  
Operating Conditions ◽  
Ansys Fluent

Abstract. The aerodynamic characteristics of DTU-LN221 airfoil is studied. ANSYS Fluent is used to simulate the airfoil performance with seven different turbulence models. The simulation results for the airfoil with different turbulence models are compared with the wind tunnel experimental data performed under the same operating conditions. It is found that there is a good agreement between the computational fluid dynamics (CFD) predicted aerodynamic force coefficients with wind tunnel experimental data especially with angle of attack between −5° to 10°. RSM is chosen to investigate the flow field structure and the surface pressure coefficients under different angle of attack between −5° to 10°. Also the effect of changing air temperature, velocity and turbulence intensity on lift and drag coefficients/forces are examined. The results show that it is recommended to operate the wind turbines airfoil at low air temperature and high velocity to enhance the performance of the wind turbines.

Wake measurements of oscillating supercritical airfoil in compressible flow

2019 ◽  
Vol 43 (1) ◽  
pp. 112-121
Author(s):  
Behnaz Beheshti Boroumand ◽  
Mahmoud Mani
Keyword(s):  
Mach Number ◽  
Angle Of Attack ◽  
Time History ◽  
Mean Value ◽  
Hot Wire ◽  
Dynamic Tests ◽  
Flow Parameters ◽  
Free Stream Mach Number ◽  
Static And Dynamic Tests ◽  
Wake Characteristics

Boundary layer and wake behaviors are strongly affected by airfoil motion. Moreover, parameters like body oscillation frequency, oscillation type, Mach number, and angle of attack play main roles in wake characteristics. In this research, both static and dynamic tests were carried out in a tri-sonic wind tunnel to study wake profiles experimentally by hot wire anemometry. All data were recorded at a free stream Mach number of 0.4. Quarter-length and half-length of chord were also considered as downstream distances from the trailing edge in pitching motions of mean angle of attack of −0.4°. Frequencies of 3 Hz and 6 Hz with amplitude of 3° were chosen as oscillation parameters. Voltages at hot wire outputs were measured and analyzed qualitatively and statistically with root-mean-square, correlation, mean value distribution, time history, and frequency. Flow parameters were obtained by computational studies under similar experimental test conditions. The wake characteristics obtained from numerical and experimental methods were compared.

scholarly journals Method of approximation of ballistic missile aerodynamic characteristics at the powered flight segment depending on the Mach number and angle of attack

2021 ◽  
pp. 57-63
Author(s):  
P. A. Krasheninnikov
Keyword(s):  
Mach Number ◽  
Drag Coefficient ◽  
Angle Of Attack ◽  
Aerodynamic Characteristics ◽  
Ballistic Missile ◽  
Aerodynamic Coefficients ◽  
Calculation Process ◽  
The Impact

The paper describes the impact of aerodynamic coefficients on the ballistic target (BT) velocity and proposes a method of approximation of the dependence of ballistic target drag coefficient Cxa on the Mach number and angle of attack. The paper proves that the proposed approach allows to substantially reduce errors in drag coefficient simulation, but requires a more complicated calculation process.

Influencing Factors Analysis of the Shock-Induced Separation for Supercritical Airfoil

2013 ◽  
Vol 444-445 ◽  
pp. 221-226
Author(s):  
Xin Xu ◽  
Da Wei Liu ◽  
De Hua Chen ◽  
Yuan Jing Wang
Keyword(s):  
Mach Number ◽  
Influencing Factors ◽  
Stokes Equations ◽  
Reynolds Numbers ◽  
Aerodynamic Characteristics ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Supercritical Airfoil ◽  
Factors Analysis ◽  
Mach Numbers

The shock-induced separation easily occurred on the upper surface of supercritical airfoil at transonic speeds, which would change the aerodynamic characteristics. The problem of the shock-induced separation was not solved completely for the complicated phenomena and flow mechanism. In this paper, the influencing factors of shock-induced separation for supercritical airfoil CH was analyzed at transonic speeds. The Navier-Stokes equations were solved, in order to investigate influence of different attack angles, Mach numbers and Reynolds numbers. The computation attack angles of CH airfoil varied from 0oto 7o, Reynolds numbers varied from 5×106to 50×106per airfoil chord while Mach number varied from 0.74 to 0.82. It was shown that the shock-induced separation was affected by attack angles, Mach numbers and Reynolds numbers, but the influence tendency and areas were quite different. The shock wave location and intensity were affected by the three factors, and the boundary layer thickness was mainly affected by Reynolds number, while the separation structure was mainly determined by the attack angle and Mach number.

The aeroelastic characteristics of high aspect ratio wing

2016 ◽  
Vol 230 (14) ◽  
pp. 2543-2556
Author(s):  
Fan Yang ◽  
Zhufeng Yue ◽  
Lei Li
Keyword(s):  
Aspect Ratio ◽  
Large Deformation ◽  
High Aspect Ratio ◽  
Data Exchange ◽  
Stokes Equations ◽  
Great Influence ◽  
Aerodynamic Characteristics ◽  
Interface Problem ◽  
Numerical Result ◽  
Computational Structural Mechanics

Owing to the elasticity, the large deformation was brought in the high aspect ratio wing in the flight. The large deformation had a great influence on the flight performance. In this paper, the loosely coupled method was used for the research of high aspect ratio wing aeroelastic problems. The Navier–Stokes equations were solved for fluid domain computation, and the nonlinear finite element method was adopted for solid domain computation. The data exchange program and mesh regeneration progress were adopted for fluid–structure interface problem. Finally, the aerodynamic characteristics of high aspect ratio wing were obtained under different fly conditions. In addition, to validate the proposed method, the flutter analysis of AGARD 445.6 wing is carried out and compared with the experimental data. The numerical result validates the proposed computational fluid dynamics/computational structural mechanics method.

scholarly journals Research on high attack angle stall and spin characteristics with flight test of a general electric aircraft

2021 ◽  
Vol 39 (3) ◽  
pp. 650-659
Author(s):  
Yadong Li ◽  
Junyao Zhang ◽  
Fengtian Yang ◽  
Yongliang Chen
Keyword(s):  
Numerical Simulation ◽  
Aspect Ratio ◽  
Aerodynamic Force ◽  
Angle Of Attack ◽  
Wind Tunnel Test ◽  
Flight Test ◽  
High Angle ◽  
High Angle Of Attack ◽  
Linear Change ◽  
Electric Aircraft

When the aircraft is flying at high angle of attack, the local separation of the air flow on the surface of the aircraft, the linear change of aerodynamic force is destroyed, and the maneuverability and stability are reduced to varying degrees, resulting in the aircraft stalling or entering the spin. The stall characteristics and spin characteristics directly affect the safety of the aircraft. In order to analyze the stall and spin characteristics, a full-scale 6-DOF nonlinear high angle of attack dynamic model is established for a two-seater electric high aspect ratio aircraft based on the wind tunnel test data. The stall characteristics of an electric aircraft at high angle of attack are obtained by numerical simulation and analysis. According to the stall characteristics of simulation calculation, flight test is carried out to verify the reliability of numerical simulation, which provides reference for the later analysis of stall/spin test of large aspect ratio series electric aircraft at nonlinear high angle of attack.

scholarly journals Effects of Trailing Edge Deflections Driven by Shape Memory Alloy Actuators on the Transonic Aerodynamic Characteristics of a Super Critical Airfoil

Actuators ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 160
Author(s):  
Binbin Lv ◽  
Yuanjing Wang ◽  
Pengxuan Lei
Keyword(s):  
Mach Number ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Angle Of Attack ◽  
Aerodynamic Characteristics ◽  
Smart Structure ◽  
Trailing Edge ◽  
Edge Based ◽  
Constant Deformation ◽  
Transonic Wind Tunnel

A smart structure to actuate a morphing trailing edge based on the super critical airfoil NASA sc-0714(2) was designed and verified in a transonic wind tunnel. The pressure distribution over the wing was measured to evaluate the structure ability and effects of trailing edge deflections on the aerodynamic characteristics. In the experiment, Mach number was from 0.4 to 0.8, and the angle of attack was from 0° to 6°. The results showed that the smart structure based on shape memory alloy could carry aerodynamic loads under transonic flow and deflect the trailing edge. When the driving force was constant, deformation would be influenced by the Mach number and angle of attack. Increasing the Mach number weakened the actuation capability of the smart structure, which decreased the deflection angle and rate of the trailing edge. The influence of the angle of attack is more complex, and couples with the influence of the Mach number. The higher the Mach number, the stronger the influence of the angles of attack. Additionally, the trailing edge deflection would dramatically change the flow structure over the airfoil, such as the shock wave position and strength. If separation was caused by the trailing edge deflection, the limitation of the smart structure would be further found.

scholarly journals Disturbed motion of the hypersonic first stage of an aerospace system in climb

2019 ◽  
Vol 18 (3) ◽  
pp. 16-28
Author(s):  
V. L. Balakin ◽  
M. M. Krikunov
Keyword(s):  
Aerodynamic Force ◽  
Angle Of Attack ◽  
Aerodynamic Characteristics ◽  
Atmospheric Density ◽  
Optimal Angle ◽  
Control Programs ◽  
Target Values ◽  
Standard Values ◽  
Reference Atmosphere ◽  
Disturbed Motion

Disturbed motion of the hypersonic first stage of an aerospace system in climb is analyzed. Deviations of atmospheric density from standard values and deviations of aerodynamic force coefficients from reference values are taken as disturbances. Disturbance motion of the hypersonic first stage of a hypersonic vehicle with the optimal angle-of-attack schedule obtained for reference atmosphere and nominal aerodynamic characteristics is modeled. Deviations of terminal conditions of disturbed motion from the target values of velocity, altitude and flight path inclination are determined. The problem of minimum propellant mass consumed in the climb with acceleration to hypersonic velocity is solved for disturbed motion by the method of Pontryagin’s maximum principle. Optimal angle-of-attack schedules, optimal flight paths and finite values of the mass of the hypersonic first stage are determined. Comparative analysis of optimal control programs and flight paths for disturbed and undisturbed motion is made.

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