Gaku Yoshikawa

Numerical analysis of transitional behavior of ferrofluid employing MPS method and FEM

This paper proposes a coupled method of finite-element method (FEM) and moving particle semi-implicit (MPS) method in order to analyze the spike shape of ferrofluid. In this method, magnetic field equation is calculated by FEM and fluid equation is calculated by MPS method.

Numerical analysis of electromagnetic levitation of molten metal employing MPS method and FEM

This paper proposes a coupled method of 3D-FEM (finite element method) and MPS (moving particle semi-implicit) method for analyzing the electromagnetic levitation of a molten metal. In this method, the magnetic field equation is calculated by FEM and fluid motion equation of a molten metal is calculated by MPS method. To verify the effectiveness of this method, it is applied to analysis of the behavior of molten metal in electromagnetic levitation.

Numerical Analysis of Cold Crucible Induction Melting Employing FEM and MPS Method

This paper proposes a coupled method of 3-D finite element method (FEM) and moving particle semi-implicit (MPS) method for the analysis of cold crucible induction melting. In this method, the magnetic field is calculated by FEM and the fluid motion equation of the molten metal and the thermal distribution in the molten metal are calculated by the MPS method. In this paper, the phase transformation of the metal is not considered. The effectiveness of this method is verified through the analysis of the molten metal behavior in the crucible.

Study on Analysis Method for Ferrofluid

In this paper, we study a new analysis method to calculate the shape of ferrofluid spikes. The shape of a ferrofluid is influenced by the magnetic force, surface force, and gravity. Therefore, the electromagnetic field equation is coupled with Navier-Stokes equation employing the moving particle semi-implicit (MPS) and the finite-element method (FEM). This paper describes the analysis algorithm of coupled method, and the comparison of calculated and measured results.

Numerical Analysis of Negative Ion by Electrostatic Atomization Employing FEM and MPS Method

This paper proposes a coupled method of 3-D finite element method (FEM) and Moving Particle Semi-implicit (MPS) method for the analysis of a negative ion that is produced by electrostatic atomization. In this method, the electric field is calculated by FEM and the fluid motion equation of a drop of water is calculated by the MPS method. The validity of this analysis method is verified by comparison with an experiment.

Analysis of the Disintegration of Charged Droplets Employing Boundary Element Method and Particle Method

It is well known that an initially charged droplet disintegrates repeatedly into several tiny sibling droplets and one parent droplet if the charge exceeds a certain value defined by the Rayleigh Limit. Many researchers have experimentally verified this phenomenon in their works. However, it is difficult to estimate the number, charge and mass of the sibling droplets because the sizes of the droplets are generally very small. In this paper, a new coupled analysis method for the disintegration of dielectric charged droplets employing boundary element method (BEM) and particle method is proposed. The behavior of the droplet during disintegration is analyzed by means of this method.

Meshless Method Based on Weighted Least Square Method for Electrohydrodynamic Problems

This paper proposes a meshless method based on the weighted least square method for electrohydrodynamic problems. In this paper, the behavior of a water droplet in a uniform electric field is calculated by this method. The effectiveness of this analysis method is verified through comparison between the analyzed result and theoretical result of the electric potential around the droplet.

Coupled 3-D Analysis Employing FEM and Particle Method—Experimental Verification of Cold Crucible Induction Melting

This paper proposes a coupled 3-D finite element method (FEM) and particle method for the analysis of cold crucible induction melting. In this method, the magnetic field is calculated by FEM and the fluid motion equation and the heat equation of a molten metal are calculated by the particle method. The effectiveness of this method is verified through the analysis of the molten metal behavior in the crucible.

Numerical Simulation Model for FSW Employing Particle Method – Effect of Tool Angle on Fluid Motion

The friction stir welding (FSW) is known as non-melting joining. It used widely in the field of industry. Numerical analysis models for FSW also have been developed. In these models, the most frequently used method is a grid method (finite element method or finite difference method). However it is difficult or troublesome to calculate the advective term both for momentum and temperature employing these methods. It is also difficult to calculate the big deformation of the materials free surface. Moreover, complex process is required to analyze the dissimilar joining with respect to dealing with substance transfer. In this paper, to avoid these difficulties, particle method is adopted for FSW simulation. In particle method, advective term, substance transfer, and surface deformation are calculated automatically mainly because that Lagrangian approach is used. To verify the effectiveness of this method, fluid motion around the tool is examined by particle trace. As a result, relations between the rotating speed of the tool and area of plastic flow is evaluated.

Analysis method of negative ion by electrostatic atomization

Purpose – The purpose of this paper is to propose an analysis method of negative ion by electrostatic atomization. Because the electrostatic atomization includes large deformation of a drop of water, it is difficult to analyze with conventional fluid analysis methods such as the finite differences method, the finite element method (FEM) and so on.Design/methodology/approach – In this method, electrostatic field equation is coupled with Navier‐Stokes equation of a drop of water, employing the moving particle semi‐implicit method and FEM. The validity of the method is verified through the measurement.Findings – It was found that the difference between calculated and measured results becomes large as the voltage increases.Research limitations/implications – In order to improve the accuracy, it is necessary to improve the way to calculate surface tension and the analysis condition.Originality/value – This paper confirms the usefulness of the numerical method to elucidate electrostatic atomization.