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The purpose of this paper is to theoretically investigate the thermal and hydrodynamic performance of the flow pattern of fluid in the charged jet. The flow pattern includes laminar flow in which all fluid layers move at different accelerated speeds, and shear forces between the fluid layers give rise to friction forces. This is a favorable condition for the parallel arrangement of the branches on polymer molecules.

The dynamic mechanism of the flow pattern is conducted through analyzing the forces acting on the charged jet. The differential equation obtained in the analyzing process has the solution designating the laminar flow pattern of the fluid in the charged jet.

The fluid in the charged jet flows in laminar pattern, which is favorable to the parallel arrangement of the branches on polymer molecules.

Although the flow pattern is conveyed by means of the simple condition of uniformly accelerated motion, it has the similar effect on the arrangement of the polymer molecules in general conditions, such as non-Newtonian fluids and non-uniformly accelerated motions.

The laminar flow introduced by this paper to the charged jet implies anisotropic properties of the electrospun nanofibers.

This study aims to present a numerical analysis of the behavior of the electric field and flow field characteristics under electrohydrodynamics (EHD) force. The influence of the jet airflow under the EHD force is investigated when it impacts the inclined flat plate.

The high electrical voltage and angle of an inclined flat plate are tested in a range of 0–30 kV and 0–90^°, respectively. In this condition, the air is set in a porous medium and the inlet jet airflow is varied from 0–2 m/s.

The results of this study show that the electric field line patterns increase with increasing the electrical voltage and it affects the electric force increasing. The angle of inclined flat plate and the boundary of the computational model are influenced by the electric field line patterns and electrical voltage surface. The electric field pattern is the difference in the fluid flow pattern. The fluid flow is more expanded and more concentrated with increasing the angle of an inclined flat plate, the electrical voltage and the inlet jet airflow. The velocity field ratio is increased with increasing the electrical voltage but it is decreased with increasing the angle of the inclined flat plate and the inlet jet airflow.

The maximum Reynolds number, the maximum velocity field and the maximum cell Reynolds number are increased with increasing the electrical voltage, the inlet jet airflow and the angle of the inclined flat plate. In addition, the cell Reynolds number characteristics are more concentrated and more expanded with increasing the electrical voltage. The pattern of numerical results from the cell Reynolds number characteristics is similar to the pattern of the fluid flow characteristics. Finally, a similar trend of the maximum velocity field has appeared for experimental and numerical results so both techniques are in good agreement.

A fluid moving system for producing substantially laminar flow of ambient fluid over and adjacent a substantially smooth surface exposed to the fluid which comprises a multiplicity of electrode elements mounted in spaced relationship to one another adjacent to the surface and electrically insulated from one another and constituting a series of elements extending along a portion of the surface. The means comprise a multiplicity of sharp points on predetermined ones of the elements oriented in the direction of flow of fluid over the elements for producing charged particles adjacent to the predetermined ones of the elements. All of the sharp points for each of the elements lie substantially in a plane perpendicular to the direction of fluid flow and equidistant from the next element in the direction of flow whereby the production of charged particles by a corona‐type discharge is facilitated at each of the sharp points. Electric exciting means connected with the electrode elements produce progressively changing electric potentials along the surface thereby creating an electric potential field for propelling charged particles dispersed in the ambient fluid progressively from one electrode clement toward the next and induce a surface layer fluid flow over that portion of the surface. Certain of the predetermined elements comprise conducting bars having the sharp points arranged in two sets pointing in opposite directions, auxiliary electrodes spaced from the bars one on one side and one on the other of each of the bars, and switching means for selectively connecting each of the bars alternatively to the auxiliary electrode on either side thereof for reversing the direction of corona discharge and the direction of charged particle propulsion.

IN a recent article on the protection of refractories in steel‐making furnaces, Chesters et al. discussed the application to furnace design of jets blown over surfaces. The theory of the wall jet is given by Glauert, who mentions as typical examples the flow produced on the ground by the downward directed jet of a vertical take‐off aircraft, and the flow produced under certain circumstances in canal sections separated by a sluice. Jacob et al. and also Zerbe and Selna have reported experiments on wall jets which were carried out as background work to the general problems of ice and fog formation on the inside surface of aircraft windshields. Other experiments have been carried out by Förthmann and also by Sigalla and Painz in the Fluid Dynamics Section of the British Iron and Steel Research Association, Physics Department.

An electrospinning process is a multi-phase and multi-physics process. The purpose of this paper is to numerically simulate the two-phase flow in the electrospinning process. The numerical results can offer in-depth insight into physical understanding of many complex phenomena which cannot be fully explained experimentally.

The two-phase flow can be calculated by solving the modified Navier-Stokes equations under the influence of electric field and the interface between the two fluids has been determined by using the Volume of Fluids (VOF) method. A realizable k-e model is used to model the turbulent viscosity. The numerical results can be obtained using Computational Fluid Dynamics (CFD) techniques.

The numerical simulation is a powerful tool to controlling over electrospinning parameters such as voltage, flow rate, and others.

The numerical simulation of two-phase flow model will take into account solvent evaporation and solidification of the jet, which play pivotal roles in determining the internal fiber morphology of the jet to be described here.

This paper deals with studying numerically the two-phase flow in the electrospinning process by applying CFD techniques. And the flow is modeled by ANSYS(FLUENT) using the VOF model.

This paper aims to summarize the latest developments both in terms of theoretical understanding and experimental techniques related to inkjet fluids. The purpose is to provide practitioners a self-contained review of how the performance of inkjet and inkjet-based three-dimensional (3D) printing is fundamentally influenced by the properties of inkjet fluids.

This paper is written for practitioners who may not be familiar with the underlying physics of inkjet printing. The paper thus begins with a brief review of basic concepts in inkjet fluid characterization and the relevant dimensionless groups. Then, how drop impact and contact angle affect the footprint and resolution of inkjet printing is reviewed, especially onto powder and fabrics that are relevant to 3D printing and flexible electronics applications. A future outlook is given at the end of this review paper.

The jettability of Newtonian fluids is well-studied and has been generalized using a dimensionless Ohnesorge number. However, the inclusion of various functional materials may modify the ink fluid properties, leading to non-Newtonian behavior, such as shear thinning and elasticity. This paper discusses the current understanding of common inkjet fluids, such as particle suspensions, shear-thinning fluids and viscoelastic fluids.

A number of excellent review papers on the applications of inkjet and inkjet-based 3D printing already exist. This paper focuses on highlighting the current scientific understanding and possible future directions.

The purpose of this paper is to investigate the applicability of the smoothed particle hydrodynamics (SPH) method in the jet formation process of a cylindrical-shaped charge (CSC). Different SPH formulations, suggested in other works, to other applications, are brought together in order to build a model that represents the phenomenon of detonation of a CSC in a more realistic way.

A two-dimensional (2D) SPH formulation using cylindrical coordinates is adopted to simulate CSCs. The problem of fluid-solid interaction between the detonation wave of the explosive and the metal liner, numerically unstable due to the great difference in density between the phases, is resolved adopting the multi-phase strategy. A new proposition of artificial viscosity is incorporated in order to account the convergence effect of the liner particles toward the axis of symmetry of the charge. Two numerical examples are used to validate the formulation. In the first, the velocity and length differences between the jets formed from a CSC and a linear-shaped charge (LSC) using planar detonation on both are compared. In the second example, the effect of the conical cavity angle in the maximum jet velocity is evaluated, comparing the simulated results of CSC with four different cavity angles, with the experimental results.

The results show that the 2D SPH method in cylindrical coordinates is able to simulate the detonation process of a CSC. Accordingly with the formulations used, the following conclusions can be made: the multi-phase strategy is able to capture the multi-material interface of the fluid-solid interaction between the detonation wave and the metal liner; and in the cylindrical geometry, a second artificial viscosity is necessary in order to include the convergence effect of the particles toward the axis of symmetry and obtaining more realistic results for the jet velocity.

The applicability of the SPH method to simulate LSCs has been tested and verified in other works, but there are not references that address the application of the SPH method to simulate CSCs. CSCs are widely used in the defense industry and in the oil industries. In the oil industry, the perforating process may currently be the most common use of such a device. For this reason, it is believed that the proposed formulation in this paper is a good alternative to these specific applications.

For the past decade, plasma actuators have been identified as a subset in the realm of active flow control devices. As research into plasma actuators continues to mature, computational modelling is needed to complement the investigation of the actuators. This paper seeks to address these issues.

In this study, the Suzen‐Huang model is chosen because of its ability to simulate both the charge density and Lorentz body force. Its advantages and limitations have been identified with a parametric study of two constants used in the modelling: the Debye length (λD) and the maximum charge density value (ρc* ). By varying the two scalars, the effects of charge density, body force and induced velocity are examined.

The results show that the non‐dimensionalised body force (Fb*) is nonlinearly dependent on Debye length. However, a linear variation of Fb* is observed with increasing values of maximum charge density. The optimized form of the Suzen‐Huang model shows better agreement in the horizontal velocity profile but still points to inaccuracy when compared to vertical velocity profile.

The results indicate that the body force still has to be modelled more extensively above the encapsulated electrode, so that the horizontal and vertical components of induced velocities are accurately obtained.

With the great advances made during the last decade or so in the fields of rocket engineering, materials research, supersonic aerodynamics, electronics and nuclear physics, the problem of extra‐terrestrial space flight has been removed from the realm of fantasy to the field of large‐scale engineering problems. Rocket‐powered reaction units occupy a leading position in the field of aeronautical research relating to high speeds, and the industrial application of atomic power is the object of many huge projects at present under development.

EVERYBODY travelling in air or water by its own power applies the reaction or “repulse” principle, that is to say, it either takes up parts of masses contained within itself or, by means of suitable organs, gathers up parts of the surrounding fluid medium and accelerates these masses at a speed greater than its own travelling speed, and this generally in the direction opposite to that in which it desires to travel; whilst in certain cases, in addition to the force produced by the repulse, a further force is obtained through the forward suction of the fluid medium. Devices intended to utilize only the negative pressure produced by suction, e.g. through lateral ejection by means of radial surfaces running at very high (five‐figure) r.p.m. have not, in spite of repeated endeavours, proved successful.