scholarly journals Analysis of the Magnus Moment Aerodynamic Characteristics of Rotating Missiles at High Altitudes

2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Yihang Xu ◽  
Shaosong Chen ◽  
Hang Zhou
Keyword(s):  
Boundary Layer ◽  
Angle Of Attack ◽  
Lateral Force ◽  
Aerodynamic Characteristics ◽  
High Altitudes ◽  
Magnus Force ◽  
Moment Coefficient ◽  
Pitch Moment ◽  
Sst Model ◽  
Force Direction

The Magnus moment characteristics of rotating missiles with Mach numbers of 1.3 and 1.5 at different altitudes and angles of attack were numerically simulated based on the transition SST model. It was found that the Magnus moment direction of the missiles changed with the increase of the angle of attack. At a low altitude, with the increase of the angle of attack, the Magnus moment direction changed from positive to negative; however, at high altitudes, with the increase of the angle of attack, the Magnus moment direction changed from positive to negative and then again to positive. The Magnus force direction did not change with the change of the altitude and the angle of attack at low angles of attack; however, it changed with altitude at an angle of attack of 30°. When the angle of attack was 20°, the interference of the tail fin to the lateral force of the missile body was different from that for other angles of attack, leading to an increase of the lateral force of the rear part of the missile body. With the increasing altitude, the position of the boundary layer with a larger thickness of the missile body moved forward, making the lateral force distribution of the missile body even. Consequently, Magnus moments generated by different boundary layer thicknesses at the front and rear of the missile body decreased and the Magnus moment generated by the tail fin became larger. As lateral force directions of the missile body and the tail were opposite, the Magnus moment direction changed noticeably. Under a high angle of attack, the Magnus moment direction of the missile body changed with the increasing altitude. The absolute value of the pitch moment coefficient of the missile body decreased with the increasing altitude.

scholarly journals Study of board bending degree on hydrodynamic performances of a single-layer cambered otter-board

2019 ◽  
Vol 131 ◽  
pp. 01120
Author(s):  
Lei Wang ◽  
Lu Min Wang ◽  
Yong Li Liu ◽  
Wen Wen Yu ◽  
Guang Rui Qi ◽  
...  
Keyword(s):  
Center Of Pressure ◽  
Lift Coefficient ◽  
Pressure Coefficient ◽  
Angle Of Attack ◽  
Single Layer ◽  
Moment Coefficient ◽  
Pitch Moment ◽  
Engineering Models ◽  
Drag Ratio ◽  
Lift To Drag Ratio

The effect of board bending degree on hydrodynamic performances of a single-layer cambered otter-board was investigated using engineering models in a wind tunnel. Three different bending degree boards were evaluated at a wind speed of 28 m/s. Parameters measured included: drag coefficient Cx, lift coefficient Cy, pitch moment coefficient Cm, center of pressure coefficient Cp , over a range of angle of attack (0° to 70°). These coefficients were used in analyzing the differences in the performance among the three otter-board models. Results showed that the bending of the board(No. 2, No. 3) increased the water resistance of the otter-board, and improved the lift coefficient of the otter-board in the small angle of attack (0°<α≤20 °) ; the maximum lift coefficients Cy of otter-board model (No. 1) was higher (1.680, α = 25°). the maximum lift–drag ratios of models (No. 1, No. 2 and No. 3) are 6.822 (α = 7.5 °), 6.533 (α = 2.5 °) and 6.384 (α = 5.0°), which showed that the board bending reduces the lift-to-drag ratio of the otter-board.The stability of the No. 3 model was better than those two models (No. 1, No. 2) in most range of attack angle, but No. 1 otter-board model had a better stability in roll of otter-board. The findings of this study can offer useful reference data for the structural optimization of otter-boards for trawling.

scholarly journals The Influence of Boundary Layer Caused by Riblets on the Aircraft Surface

2020 ◽  
Vol 10 (11) ◽  
pp. 3686
Author(s):  
Hongqing Lv ◽  
Zhenqing Wang ◽  
Jiahao Chen ◽  
Lei Xu
Keyword(s):  
Boundary Layer ◽  
Drag Reduction ◽  
Flow Direction ◽  
Angle Of Attack ◽  
Suction Side ◽  
Aerodynamic Characteristics ◽  
Wall Surface ◽  
Friction Resistance ◽  
Naca0012 Airfoil ◽  
Stall Angle

Drag reduction of riblets is one of the most important problems in drag reduction of non-smooth surfaces. In the past two decades, the use of riblets arranged along the flow direction to reduce frictional resistance has received considerable attention. In this paper, we study the plates with the triangular concave grooves, triangular protrusion riblets, trapezoidal concave grooves, trapezoidal protrusion riblets, and circular concave grooves. The numerical simulation method is used to calculate five kinds of plates with grooves and riblets under multiple working conditions. The results showed that the plates with grooves and riblets generated vortices inside the grooves, which separated the incoming flow from the wall surface, and by increasing the thickness of the boundary layer, greatly reducing the average velocity gradient of the wall surface, compared with the smooth flat plate, the friction resistance is reduced. But, lateral riblets and grooves cause additional pressure resistance, which is one order of magnitude higher than the friction resistance. Then, the triangular concave grooves are arranged on the suction and pressure sides of the NACA0012 airfoil, respectively. We calculated the aerodynamic parameters of the both airfoils, and the standard NACA0012 airfoil from the −8° attack angle to their respective stall attack angles. The results showed that the NACA0012 airfoil with triangular concave grooves on the suction side reduced the aerodynamic characteristics of the standard NACA0012 at a small angle of attack, but the stall angle of attack of the standard NACA0012 airfoil was improved, because the grooves ensure that some gas can flow normally on the suction side and delay the separation of the boundary layer. The NACA0012 airfoil with triangular concave grooves on the pressure side did not effectively improve the aerodynamic characteristics: lift–drag ratio decreased and stall angle of attack decreased, but it can increase the lift slightly.

Flight Development of the Avro CF-100 Mark 5 Aircraft

1958 ◽  
Vol 62 (566) ◽  
pp. 118-122 ◽  
Author(s):  
D. C. Whittley
Keyword(s):  
Boundary Layer ◽  
Shock Wave ◽  
Aspect Ratio ◽  
Aerodynamic Characteristics ◽  
Vortex Generators ◽  
High Altitudes ◽  
Trailing Edge ◽  
Flap Deflection ◽  
Performance Gains

SummaryImprovements made to the aerodynamic characteristics of the wing of the Avro CF-100 Mark 5 aircraft are discussed. Modifications to the wing included increase in aspect ratio, addition of vortex generators, and deflection of trailing edge plain flaps. The effect of flap deflection and addition of vortex generators on the aerodynamic characteristics of the wing are shown to be closely associated with interaction of the upper surface shock wave with the boundary layer. Performance gains were demonstrated at high subsonic speeds at high altitudes. Vortex generators improved the buffet boundary, whereas flap deflection both increased aircraft ceiling and improved buffet boundary.

Numerical Simulation of the Three Component Coefficients of Bridge

2012 ◽  
Vol 430-432 ◽  
pp. 2004-2007
Author(s):  
Yi Feng Huang ◽  
Ji Xin Yang
Keyword(s):  
Numerical Simulation ◽  
Wind Speed ◽  
Drag Coefficient ◽  
Turbulence Model ◽  
Lift Coefficient ◽  
Angle Of Attack ◽  
Moment Coefficient ◽  
Pitch Moment ◽  
Airflow Field ◽  
Bridge Girder

Numerical simulation has been carried out on the airflow field of bridge girder at construction state and completed bridge state under different wind speed and different wind angle of attack. The k-ε two-equation turbulence model is used in the numerical simulation by FLUENT. Variation of the three component coefficients can be obtained. The results show that drag coefficient and lift coefficient gradually becomes smaller and tends to stabilize, while pitch moment coefficient shows the trend of first increased and then reduced as wind speed increases. Drag coefficient and pitch moment coefficient does not change much and lift coefficient gradually becomes smaller with the change of wind angle of attack.

Effect of transition on the aerodynamic characteristics of a spinning cone

2017 ◽  
Vol 232 (11) ◽  
pp. 2048-2058
Author(s):  
Qiao Zhang ◽  
Xiaosheng Wu ◽  
Jintao Yin ◽  
Ran Yao
Keyword(s):  
Boundary Layer ◽  
Layer Thickness ◽  
Boundary Layer Thickness ◽  
Stokes Equations ◽  
Turbulence Models ◽  
Aerodynamic Characteristics ◽  
Navier Stokes ◽  
Transition Model ◽  
Magnus Force ◽  
The Right

In order to study the effect of transition on the aerodynamic characteristics of a pointed cone at small angles of attack in supersonic flows, the [Formula: see text] transition model, γ transition model, and a trip wire applied with [Formula: see text] transition model coupled with the Reynolds-averaged Navier–Stokes equations were used to simulate the flow over the spinning cone. The γ transition model, including the effects of crossflow instability, is better than other models in the transition and Magnus force prediction. The numerical calculations are in certain agreement with the experimental data. The results indicate that the positions of the maximum boundary layer thickness remain unchanged using different turbulence models, while the results obtained by the transition model shift towards spin direction, intensifying the difference of the boundary layer thickness between the right and the left side bodies; the contribution of the skin friction on the Magnus force increases due to the shift in the transition position; the contribution of pressure on the Magnus force also changes with the distortion of the boundary layer.

Aerodynamic Characteristics of an Airfoil with Boundary Layer Ingestion in Subsonic Flow

2014 ◽  
Vol 670-671 ◽  
pp. 609-612 ◽  
Author(s):  
Jiang Hao Wu ◽  
Xue Mei Li
Keyword(s):  
Boundary Layer ◽  
Numerical Method ◽  
Mass Flow ◽  
Small Angle ◽  
Subsonic Flow ◽  
Angle Of Attack ◽  
Aerodynamic Characteristics ◽  
Pitching Moment ◽  
Flow Ratio ◽  
Mass Flow Ratio

The influence of boundary layer ingestion (BLI) on the aerodynamics of airfoil RAE2822 in subsonic is investigated by numerical method. Based on the calculation, it is found that the mass flow ratio (MFR), intake height, cowl length and intake position in the chord can affect on the lift, drag and pitching moment remarkable. Considering a maximum lift-over-drag, intake position in the chord should be rearward as possible with a certain high MFR at a small angle of attack and a considerable intake height. There is a proper MFR which makes drag lowest.

Influence of a rough surface on the aerodynamic characteristics of a rotating cylinder

2021 ◽  
Vol 103 (3) ◽  
pp. 52-59
Author(s):  
N.K. Tanasheva ◽  
◽  
A.R. Bakhtybekova ◽  
A.Zh. Tleubergenova ◽  
L.L. Minkov ◽  
...  
Keyword(s):  
Rough Surface ◽  
Drag Force ◽  
Air Flow ◽  
Angle Of Attack ◽  
Experimental Studies ◽  
Rotating Cylinder ◽  
Aerodynamic Characteristics ◽  
Magnus Force ◽  
Lifting Force ◽  
Relative Roughness

The article considers the influence of the relative roughness of a cylindrical blade on aerodynamic characteristics. It is known that the operation basis of blades under consideration is the Magnus effect, which is characterized by appearance of a lifting force (Magnus force), when the cylinders rotate in a transverse flow. This force is used to rotate the wind wheel, similar to lifting force, but can have a much larger value when selecting optimal conditions, both geometric and aerodynamic. The authors conducted a comparative analysis of cylinder layout with a relative roughness (0.005 ÷ 0.02). Experimental studies of aerodynamics process of rotating cylinders were carried out in the aerodynamic laboratory using the T-1-M wind tunnel at an air flow value of 5 to 15 m/s. Graphs of dependences of rotating cylinder's lifting force and drag force on the changing air flow velocity and on relative roughness, k/d, are obtained. For further study experimental cylinder layout’s aerodynamic parameters, the most optimal is the variant with a relative roughness value of 0.02, which had high indicators, was selected. In the course of experimental studies, graphs of the dependence of the values of lift and drag force on the angles of attack of a single rotating cylinder with a rough surface on the speed and angle of attack of the wind flow (0°, 30° and 60°) were obtained. It is established that the effective angle of attack is 0°, at which aerodynamic characteristics’s maximum values were obtained.

Aerodynamic characteristics of a dual-spin projectile with canards

2019 ◽  
Vol 233 (12) ◽  
pp. 4541-4553
Author(s):  
Xiaodong Liu ◽  
Xiaosheng Wu ◽  
Jintao Yin
Keyword(s):  
Mach Number ◽  
Normal Force ◽  
Angle Of Attack ◽  
Three Dimensional ◽  
Lateral Force ◽  
Aerodynamic Characteristics ◽  
Navier Stokes ◽  
Force Coefficient ◽  
Sliding Mesh ◽  
Flow Mechanisms

Based on the three-dimensional Navier–Stokes (N–S) equations, using unsteady numerical technology, flow over a dual-spin projectile was simulated to investigate its aerodynamic characteristics during flight. Spin was achieved via the sliding mesh method. The influence laws of the aftbody spin rate, Mach number, and angle of attack on the aerodynamic characteristics of the projectile are presented, and the flow mechanisms for the laws are revealed. The results demonstrate that the influence of the aftbody spin rate on the normal force coefficient is very small, whereas, on the lateral force coefficient, it is larger. With the increase in the Mach number, the time-averaged normal force coefficient and lateral force coefficient increase, while the fluctuation quantities of the normal force coefficient and the lateral force coefficient decrease. The variation of angle of attack will influence the size, distribution, and interference effect of the shedding vortices.

scholarly journals Numerical Investigation of Aerodynamic Characteristics of NACA 4312 Airfoil with Gurney Flap

2021 ◽  
pp. 1-8
Author(s):  
Subah Mubassira ◽  
Farhana Islam Muna ◽  
Mohammad Ilias Inam
Keyword(s):  
Flow Separation ◽  
Lift Coefficient ◽  
Angle Of Attack ◽  
Reynold Number ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Performance ◽  
Chord Length ◽  
Ansys Fluent ◽  
Gurney Flap ◽  
Sst Model

This paper presents a two-dimensional Computational Fluid Dynamics (CFD) analysis on the effect of gurney flap on a NACA 4312 airfoil in a subsonic flow. These numerical simulations were conducted for flap heights 1.5%, 1.75%, 2% and 3% of chord length at fixed Reynold Number, Re (5×105) for different angle of attack (0o ~16o). ANSYS Fluent commercial software was used to conduct these simulations. The flow was considered as incompressible and K-omega Shear Stress Transport (SST) model was selected. The numerical results demonstrate that lift coefficient increase up to around 12o AoA (angle of attack) for NACA 4312 with and without gurney flap. For every AoA lift coefficient and drag coefficient presented proportionate behavior with flap height. However, lift co-efficient was decreased after around  angle of attack due to flow separation. Maximum lift to drag ratio was found at around 4o AoA for every flap length and airfoil with flap of 1.5%C (chord length) had shown the most optimized aerodynamic performance through the analysis. This study concluded that airfoil with gurney flap displayed enhanced aerodynamic performance than the airfoil without gurney flap due to the delay in flow separation.

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