Ferrofluid  Thin Films for Airfoil  Lift Generation

2020 ◽  
Author(s):  
Francisco Arias
Keyword(s):  
Magnetic Field ◽  
Thin Film ◽  
Thin Films ◽  
Boundary Layer ◽  
Slip Velocity ◽  
Fluid Interface ◽  
Interfacial Velocity ◽  
Moving Wall ◽  
Air Stream ◽  
Novel Concept

Abstract In this work, consideration is given to a novel concept for airfoil lift generation and flow control. In this concept, the goal is attained by preventing the growth of the boundary layer from the elimination of the zero slip condition between the surface and the air stream. The concept would simulate all effects of a moving wall leading in the appearance of slip velocity in the gas-fluid interface including the injection of momentum into the boundary layer, with one exception: there is no moving wall but instead a ferrofluid thin film attached at the wall by a magnetic field which permit to attain much more higher velocities at the interface which is not allowable if mobil surface wall are used. Utilizing a simplified physical model for the profile velocity of the ferrofluid film and from ferrohydrodynamic stability considerations an analytical expression for the interfacial velocity was derived. Finally, from the available experimental data on moving walls the expected lift and attack angle enhancement was found. Additional R\&D is required in order to explore the possibilities in the use of ferrofluid thin films.

scholarly journals Ferrofluid thin films for aerofoil lift enhancement and delaying flow separation

2020 ◽  
Vol 124 (1282) ◽  
pp. 1865-1878
Author(s):  
F.J. Arias
Keyword(s):  
Thin Films ◽  
Boundary Layer ◽  
Flow Separation ◽  
Unit Surface Area ◽  
Moving Wall ◽  
Air Stream ◽  
Unit Surface ◽  
Weight Penalty ◽  
Lift Enhancement ◽  
Novel Concept

ABSTRACTIn this work, consideration is given to a novel concept for aerofoil lift enhancement and delaying flow separation. Here, lift enhancement is attained by preventing the growth of the boundary layer through the elimination of the zero-slip condition between the wing surface and the air stream. The concept would simulate all the effects of a moving wall, leading to the appearance of a slip velocity at the gas–fluid interface, including the injection of momentum into the air boundary layer, but with one exception: here there is no moving wall but instead a ferrofluid thin film pumped parallel and attached to the wall by a magnetic field. Utilising a simplified physical model for the velocity profile of the ferrofluid film and based on ferrohydrodynamic stability considerations, an analytical expression for the interfacial velocity is derived. Finally, from the available experimental data on moving walls, the expected lift and angle-of-attack enhancement are found as well as the weight penalty per unit surface area of the wing is estimated. Additional research and development is required to explore the possibilities of using ferrofluid thin films.

Fabrication of NdFeB Thin Film and Its Application in MEMS

2002 ◽  
Author(s):  
Pan Zheng ◽  
Mohammad Kilani ◽  
Yousef S. Haik ◽  
Ching-Jen Chen
Keyword(s):  
Magnetic Field ◽  
Thin Film ◽  
Thin Films ◽  
Magnetic Properties ◽  
Saturation Magnetization ◽  
Transmission System ◽  
Gear Transmission ◽  
Energy Product ◽  
Gear Transmission System ◽  
Residual Inductance

The paper measures the magnetic properties of NdFeB thin films developed under the effects of magnetic field. The samples exhibited a larger residual inductance, saturation magnetization and energy product than those treated without field or with weaker field. Magnetic MEMS was introduced with application of the NdFeB film to micro device such as pumps and gear transmission system.

Magnetic Domain Structures in CoNiFe Thin Films and Lines

2002 ◽  
Vol 738 ◽  
Author(s):  
Lucas Pérez ◽  
Oscar de Abril ◽  
Claudio Aroca ◽  
Pedro Sánchez ◽  
Eloísa López ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Thin Film ◽  
Thin Films ◽  
Magnetic Properties ◽  
Magnetic Anisotropy ◽  
Domain Structure ◽  
Magnetic Domain ◽  
Electrodeposition Process ◽  
Domain Structures

ABSTRACTThin films and arrays of lines of magnetic CoNiFe alloy have been produced by electrodeposition. A magnetic field was applied during the electrodeposition process in order to induce a magnetic anisotropy in the sample. The dependence of the magnetic properties and the magnetic domain structures on the thickness of the films is reported. In addition to this, the magnetic properties and the domain structure of a thin film and an array of lines, with the same thickness and deposited in the same conditions, have been compared. An increase in the coercivity of the array of lines has been shown.

scholarly journals Numerical analysis of flow and heat transfer in a thin film along an unsteady stretching cylinder

2021 ◽  
Vol 25 (Spec. issue 2) ◽  
pp. 441-448
Author(s):  
Azeem Shahzad ◽  
Bushra Habib ◽  
Muhammad Nadeem ◽  
Muhammad Kamran ◽  
Hijaz Ahma ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Thin Film ◽  
Heat Transfer ◽  
Boundary Layer ◽  
External Magnetic Field ◽  
Stretching Cylinder ◽  
Similarity Transformations ◽  
Flow And Heat Transfer ◽  
Governing System ◽  
The Impact

In this framework, the boundary-layer mass and heat flow in a liquid film over an unsteady stretching cylinder are discussed under the influence of a magnetic field. By means of the similarity transformations the highly non-linear governing system of PDE is converted to ODE. We use the built-in function bvp4c in MATLAB to solve this system of ODE. The impact of distinctive parameters on velocity and temperature profile in the existence of an external magnetic field is depicted via graphs and deep analysis is also presented.

Stark and Zeeman effects on the topological phase and transport properties of topological crystalline insulator thin films

2020 ◽  
Vol 22 (21) ◽  
pp. 12129-12139
Author(s):  
Pham Thi Huong ◽  
Chuong V. Nguyen ◽  
Huynh V. Phuc ◽  
Nguyen N. Hieu ◽  
Bui D. Hoi ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Thin Film ◽  
Thin Films ◽  
Phase Transition ◽  
Electric Field ◽  
Transport Properties ◽  
Group Velocity ◽  
Dirac Fermions ◽  
Topological Phase ◽  
Topological Crystalline Insulator

We applied a perpendicular electric field and an in-plane magnetic field to not only tune the Dirac gap of a SnTe(001) thin film and find the phase transition but also to investigate their effects on the group velocity of both massless and massive surface Dirac fermions.

Bimorph-type Magnetostrictive Actuator/Sensor Thin Films

2005 ◽  
Vol 888 ◽  
Author(s):  
Teiko Okazaki ◽  
Norimasa Okanisi ◽  
Yuki Miura ◽  
Munemi Michigami ◽  
Yasubumi Furuya ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Thin Film ◽  
Thin Films ◽  
Magnetron Sputtering ◽  
Dc Magnetic Field ◽  
Magnetostrictive Actuator ◽  
Optical Lever ◽  
Low Magnetic Field ◽  
Kapton Foil ◽  
Sputtering System

ABSTRACTGiant magnetostrictive Fe-Pd and Fe-Ga thin films are expected as actuator/ sensor materials with high respective velocity and huge stress created by the magnetostriction. In order to develop magnetostrictive material induced by low magnetic field, we investigated bimorph-type magnetostrictive (positive magnetostriction / substrate / negative magnetostriction) thin films, that is, Fe-Pd(1, 3µm) or Fe-Ga(1, 3µm)/substlate /Ni(1, 3µm) by magnetron sputtering system. The substrate is Al(50µm) or kapton foil (125µm). Displacement of a upper part of these films was measured using an optical lever method. The displacement of the Fe70-Pd30(3µm )/ Al(50µm)/Ni(3µm)film ( length is 20 mm) was 280 μm under low DC magnetic field of 500 Oe and exhibits little hysteresis. These magnetostrictive properties are maintained under low alternating magnetic field. Moreover, the displacement of the film at the resonance frequency exhibits a peak and reached to 1.4 mm. The bimorph-type magnetostrictive thin film is useful for application in micro device as micro-pomp.

Effect of Domain Structure on the Magnetoresistance of Epitaxial Thin Films of Ferromagnetic Metallic Oxide SrRuO3

1997 ◽  
Vol 494 ◽  
Author(s):  
R. A. Rao ◽  
D. B. Kacedon ◽  
C. B. Eom
Keyword(s):  
Magnetic Field ◽  
Thin Film ◽  
Thin Films ◽  
Domain Structure ◽  
Applied Magnetic Field ◽  
Spin Fluctuations ◽  
Negative Magnetoresistance ◽  
Epitaxial Thin Films ◽  
Metallic Oxide ◽  
Domain Structures

ABSTRACTWe have grown epitaxial ferromagnetic metallic oxide SrRuO3 thin films with different domain structures on (001) LaAlO3 and miscut (001) SrTiO3 substrates. The effect of crystallographic domain structures on the magnetization and magnetoresistive behavior of epitaxial SrRuO3 thin films has been studied. Magnetization measurements on the single domain film on 2° miscut (001) SrTiO3 substrate showed that the in-plane [110] direction, which is aligned along the miscut direction, is the easier axis for magnetization compared to the [001] direction. This film also showed a strong anisotropie magnetoresistance (AMR) effect of ∼ 8% in magnitude. In contrast, the SrRuO3 thin film on (001) LaAlO3 substrate shows identical magnetization and magnetoresistance behavior in two orthogonal directions on the film due to the presence of 90 domains in the plane. For both the films, large negative magnetoresistance effects (-10%) were observed when the current and the applied magnetic field are parallel. The magnetoresistance behavior is explained in terms of suppression of spin fluctuations near Tc and the AMR effect.

scholarly journals Inducing Crystallinity of Metal Thin Films with Weak Magnetic Fields without Thermal Annealing

Crystals ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 362 ◽  
Author(s):  
Stefan Ručman ◽  
Winita Punyodom ◽  
Jaroon Jakmunee ◽  
Pisith Singjai
Keyword(s):  
Magnetic Field ◽  
Thin Film ◽  
Thin Films ◽  
Energy Efficient ◽  
Environmentally Friendly ◽  
Nitrogen Flow ◽  
Pure Nitrogen ◽  
Atmospheric Air ◽  
Thin Film Fabrication ◽  
Film Fabrication

Since the discovery of thin films, it has been known that higher crystallinity demands higher temperatures, making the process inadequate for energy-efficient and environmentally friendly methods of thin film fabrication. We resolved this problem by sparking metal wires in a 0.4 Tesla magnetic field at ambient conditions under ultra-pure nitrogen flow to replace the annealing of thin films, and thus designed an environmentally friendly and energy-efficient thin film fabrication method. We employed grazing incidence X-Ray Diffraction spectroscopy to characterize crystallinity of Iron, Nickel, Copper and Tungsten thin films prepared by a sparking discharge process in the presence of 0.4 T magnetic field at an ambient temperature of 25 °C. Control experiment was conducted by sparking without a magnetic field present and using ultra-pure nitrogen flow and ambient air containing oxygen. The Iron thin film prepared in ultra-pure nitrogen flow preserved crystallinity even after one year of ageing. Nickel exhibited higher crystallinity when sparked in nitrogen gas flow than when sparked in atmospheric air and was the only element to crystalize under atmospheric air. Tungsten successfully crystalized after just 40 min of sparking and aluminium failed to crystalize at all, even after 12 h of sparking under nitrogen flow.

Enhancing Superconducting Parameters by Array of External Magnetic Dots

2009 ◽  
Vol 1180 ◽  
Author(s):  
Wei Jiang Yeh ◽  
Bo Cheng
Keyword(s):  
Magnetic Field ◽  
Thin Film ◽  
Thin Films ◽  
Pinning Force ◽  
High Tc Superconductors ◽  
High Tc ◽  
Current Value ◽  
Magnetic Dots ◽  
The Magnetic Field ◽  
Superconducting Parameters

AbstractEnhancing the pinning force in high-Tc superconductors can be achieved by externally introduced periodic magnetic dots. We use a novel nano-technique to deposit periodic sub-micon Ni dots on YBa2Cu3O7 thin films. The current versus voltage characteristics of an YBa2Cu3O7 thin film strip with uniform Ni dots are measured at various temperatures and magnetic fields. They are compared with the current versus voltage characteristics of a bare YBa2Cu3O7 thin film strip without magnetic dots. It is found the critical current value of the strip with Ni dots reduces with a much slower pace as the magnetic field strength increases in comparison with the value of the bare sample.

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