Magnetic Levitation Forces—Circular Coils

1973 ◽  
Vol 51 (7) ◽  
pp. 731-736
Author(s):  
P. A. Puhach ◽  
D. L. Atherton ◽  
B. Castel
Keyword(s):  
Vector Potential ◽  
High Speed ◽  
Magnetic Levitation ◽  
Magnetic Vector Potential ◽  
Magnetic Vector ◽  
Drag Forces ◽  
Circular Coil ◽  
Lift And Drag ◽  
Drag Ratio ◽  
Lift To Drag Ratio

Magnetic vector potential is used to derive lift and drag forces for arbitrary coils moving parallel to infinite conducting slabs. It is shown that at high speed the ratio of magnetic lift-to-drag forces for a circular coil whose diameter is small in comparison with its height above the conducting slab becomes 0.6763(hλ)1/2, where λ = μσv. It is concluded that, in practice, the rounded corners needed on rectangular levitation coils will not alter the magnetic lift-to-drag ratio significantly.

scholarly journals Stress and Shape Analysis of a Paraglider Wing

1965 ◽  
Vol 32 (4) ◽  
pp. 771-780 ◽  
Author(s):  
Robert W. Fralich
Keyword(s):  
Structural Analysis ◽  
Shape Analysis ◽  
Numerical Results ◽  
Internal Stresses ◽  
Flexible Wing ◽  
Aerodynamic Pressure ◽  
Drag Forces ◽  
Lift And Drag ◽  
Drag Ratio ◽  
Lift To Drag Ratio

A combined aerodynamic-structural analysis is made which is based on the assumption that the sail is flexible and has freedom to take the shape which the aerodynamic pressure and the internal stresses dictate. Numerical results were obtained for Newtonian impact aerodynamic theory and were compared with published results obtained for a rigid idealization of the paraglider wing. It was found that the assumed rigid idealization did not approximate the shape of a flexible wing well and led to significant errors in the lift and drag forces and the lift-to-drag ratio. The new calculations provide a basis for design of paragliders for hypersonic flight.

scholarly journals Aerodynamic Performance of Biomimicry Snake-Shaped Airfoil

2019 ◽  
Vol 9 (2) ◽  
pp. 3319-3323
Keyword(s):  
Cross Section ◽  
Lift Coefficient ◽  
Design Parameters ◽  
Drag Forces ◽  
Cross Section Shape ◽  
Section Shape ◽  
Wide Range ◽  
Lift And Drag ◽  
Drag Ratio ◽  
Lift To Drag Ratio

The cross-section shape and proportionality between geometrical dimensions are the most important design parameters of any lifting surfaces. These parameters affect the amount of the aerodynamic forces that will be generated. In this study, the focus is placed on the snake-cross-section airfoil known as the S-airfoil. It is found that there is a lack of available researches on S-airfoil despite its important characteristics. A parametric study on empty model of the S-airfoil with a cross-section shape that is inspired by the Chrysopelea paradise snake is conducted through numerical simulation. Simulation using 2D-ANSYS FLUENT17 software is used to generate the lift and drag forces to determine the performance of airfoil aerodynamic. Based on the results, the S-airfoil can be improved in performance of aerodynamic by reducing the thickness at certain range, whereby changing the thickness-to-chord ratio from 0.037 to 0.011 results in the increment of lift-to-drag ratio from 2.629 to 3.257. On other hand, increasing the height-to-chord ratio of the S-airfoil will increase maximum lift coefficient but drawback is a wide range of angles of attack regarding maximum lift-to-drag ratio. Encouraging results obtained in this study draws attention to the importance of expanding the research on S-airfoil and its usage, especially in wind energy.

scholarly journals Water Energy Resource Innovation on the Cavitation Characteristics

2020 ◽  
Vol 143 (2) ◽  
Author(s):  
Mohammad D. Qandil ◽  
Ahmad I. Abbas ◽  
Tarek ElGammal ◽  
Ahmad I. Abdelhadi ◽  
Ryoichi S. Amano
Keyword(s):  
Volume Fraction ◽  
Energy Resource ◽  
Inverse Correlation ◽  
Cavitation Number ◽  
Drag Forces ◽  
Lift And Drag ◽  
Work Done ◽  
Drag Ratio ◽  
Lift To Drag Ratio ◽  
Upstream Flow

Abstract The main purpose of this study is to numerically correlate the amount of generated vapor over a hydrofoil to the lift and drag coefficients acting on it. Cavitation characteristics were investigated of a hydrofoil in the cavitating, sub-cavitating, and non-cavitating flows for different angles of attacks (AoA) with the high upstream flow velocity. The hydrofoil was tested in a square water tunnel with water entering the tunnel at various velocities for each AoA ranges from 9.1 m/s to 12.2 m/s. It was found that lift and drag forces acting on the hydrofoil follow the trend of the experimental data quite closely. While the cavitation can be identified by a unique number (averaged vapor volume fraction), the work done created an inverse correlation between this number and the cavitation number at the same angle of attack. The lift force declines with the increase in the vapor content on the hydrofoil surface, meanwhile the drag force peaks at certain vapor volume fraction, and then, a huge reduction occurs with the considerable decrease in the corresponding cavitation number. A fourth-order correlation generated between the lift to drag (L/D) and the cavitation number (σ). It was found the lift-to-drag ratio decreases by the formation of the cavitation over the hydrofoil, thus causing a drop in the efficiency of the turbomachines.

scholarly journals Experimental Investigation of a Wing-in-Ground Effect Craft

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
M. Mobassher Tofa ◽  
Adi Maimun ◽  
Yasser M. Ahmed ◽  
Saeed Jamei ◽  
Agoes Priyanto ◽  
...  
Keyword(s):  
Research Work ◽  
Ground Effect ◽  
Aerodynamic Characteristics ◽  
Aerodynamic Efficiency ◽  
Ground Clearance ◽  
Drag Forces ◽  
Lift And Drag ◽  
Drag Ratio ◽  
Lift To Drag Ratio ◽  
Wing In Ground Effect

The aerodynamic characteristics of the wing-in-ground effect (WIG) craft model that has a noble configuration of a compound wing was experimentally investigated and Universiti Teknologi Malaysia (UTM) wind tunnel with and without endplates. Lift and drag forces, pitching moment coefficients, and the centre of pressure were measured with respect to the ground clearance and the wing angle of attack. The ground effect and the existence of the endplates increase the wing lift-to-drag ratio at low ground clearance. The results of this research work show new proposed design of the WIG craft with compound wing and endplates, which can clearly increase the aerodynamic efficiency without compromising the longitudinal stability. The use of WIG craft is representing an ambitious technology that will help in reducing time, effort, and money of the conventional marine transportation in the future.

scholarly journals Cavities at atmospheric pressure behind two-dimensional bodies at an angle of attack

2005 ◽  
Vol 47 (1) ◽  
pp. 103-119
Author(s):  
P. M. Haese
Keyword(s):  
Atmospheric Pressure ◽  
Angle Of Attack ◽  
The Body ◽  
Bluff Bodies ◽  
Two Dimensional ◽  
Physical Conditions ◽  
Drag Forces ◽  
Lift And Drag ◽  
Drag Ratio ◽  
Lift To Drag Ratio

AbstractThis paper presents an interior source method for the calculation of semi-infinite cavities behind two-dimensional bluff bodies placed at an angle of attack in a uniform stream. Aspects under consideration include the pressure distribution along the body, especially just ahead of the separation point, lift and drag forces, and how these quantities vary with the angle of attack. We include discussion of the physical conditions of separation, and identify critical angles of attack for which the cavitating flow past an airfoil may (a) become unstable, or (b) yield the greatest lift to drag ratio.

scholarly journals A Perturbation Method to Analyze the Effect of Cross Section and Angle of Attack for Some Conical Bodies in Hypersonic Flow

2010 ◽  
Vol 3 (1) ◽  
pp. 52-58
Author(s):  
N. Talebanfard ◽  
A. B. Rahimi
Keyword(s):  
Perturbation Method ◽  
Cross Section ◽  
Cross Sections ◽  
Angle Of Attack ◽  
The Body ◽  
Drag Forces ◽  
Lift And Drag ◽  
Flow Variables ◽  
Drag Ratio ◽  
Lift To Drag Ratio

An analysis is performed to study the supersonic flow over conical bodies of three different cross sections circular, elliptic and squircle (square with rounded corners) shaped. Perturbation method is applied to find flow variables analytically. In order to find lift and drag forces the pressure force on the body is found, the component along x is drag and the component along z is lift. Three equations are obtained for lift to drag ratio of each cross section. The graphs for L/D show that for a particular cross section an increase in angle of attack, increases L/D. Comparing L/D in the three mentioned cross sections it is obtained that L/D is the greatest in squircle then in ellipse and the least in circle. The results have applications in design of flying objects such as airplanes where many more seats can be arranged in ellipse and or squircle cross section compared to regular circular case.

scholarly journals A Parametric Study of Trailing Edge Flap Implementation on Three Different Airfoils Through an Artificial Neuronal Network

Symmetry ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 828
Author(s):  
Igor Rodriguez-Eguia ◽  
Iñigo Errasti ◽  
Unai Fernandez-Gamiz ◽  
Jesús María Blanco ◽  
Ekaitz Zulueta ◽  
...  
Keyword(s):  
Aerodynamic Coefficients ◽  
Trailing Edge ◽  
High Lift ◽  
Trailing Edge Flaps ◽  
Artificial Neural Network Ann ◽  
Lift And Drag ◽  
Artificial Neuronal Network ◽  
Naca 0012 ◽  
Drag Ratio ◽  
Lift To Drag Ratio

Trailing edge flaps (TEFs) are high-lift devices that generate changes in the lift and drag coefficients of an airfoil. A large number of 2D simulations are performed in this study, in order to measure these changes in aerodynamic coefficients and to analyze them for a given Reynolds number. Three different airfoils, namely NACA 0012, NACA 64(3)-618, and S810, are studied in relation to three combinations of the following parameters: angle of attack, flap angle (deflection), and flaplength. Results are in concordance with the aerodynamic results expected when studying a TEF on an airfoil, showing the effect exerted by the three parameters on both aerodynamic coefficients lift and drag. Depending on whether the airfoil flap is deployed on either the pressure zone or the suction zone, the lift-to-drag ratio, CL/CD, will increase or decrease, respectively. Besides, the use of a larger flap length will increase the higher values and decrease the lower values of the CL/CD ratio. In addition, an artificial neural network (ANN) based prediction model for aerodynamic forces was built through the results obtained from the research.

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