Sergei Bronnikov¹, Sergei Kostromin, Vyacheslav Zuev

The International Conference on Computational & Experimental Engineering and Sciences, Vol.9, No.4, pp. 207-214, 2009, DOI:10.3970/icces.2009.009.207

Abstract Kinetics of the ordered phase growth in a melted multi-component liquid crystalline mixture subjected to a deep cooling was studied using polarizing optical microscopy. The droplets of the ordered phase revealed in the optical images across the phase transition were segmented and treated statistically. In the resulting histograms, two overlapping statistical ensembles related to two main components of the mixture were recognized. These ensembles were successfully described using principles of irreversible thermodynamics and the mean droplet diameters within both ensembles were determined. Analysis of the mean droplet diameter as a function of time allowed recognition More >

Davood Kalantari¹

FDMP-Fluid Dynamics & Materials Processing, Vol.5, No.1, pp. 81-92, 2009, DOI:10.3970/fdmp.2009.005.081

Abstract In this paper a theoretical approach is elaborated for modelling the impact and ensuing spreading behaviour of a liquid droplet after its collision with a flat and rigid surface. The major outcomes of such a study can be summarized as follows: 1) The propagating-shock-wave velocity associated with the droplet is not a constant value but depends on the impact velocity and the physical and geometrical properties of the droplet. 2) The initial radial ejection velocity of the lamella is proportional to the shock-wave velocity (ua) and the impact velocity (0) according to the expression (a-u0)1/2. More >

Lassig, J.¹, Montes, G., Quiroga, J.

FDMP-Fluid Dynamics & Materials Processing, Vol.5, No.1, pp. 61-80, 2009, DOI:10.3970/fdmp.2009.005.061

Abstract This paper presents a description of the design and ensuing development of an automated liquid droplet generator and related utilization aboard the space shuttle, a) as a fluid positioning system for materials processing (attached droplet method), and b) as a means to measure surface oscillation of droplets under microgravity for determining their surface tension. More >

Sayavur I. Bakhtiyarov¹, Dennis A. Siginer²

FDMP-Fluid Dynamics & Materials Processing, Vol.5, No.1, pp. 1-22, 2009, DOI:10.3970/fdmp.2009.005.001

Abstract Strong inhomogeneous magnetic fields are necessary to generate a finite levitation force in ground based electromagnetic levitation techniques. External forces such as magnetic and gravitational forces influence the oscillation spectrum and counteract the surface movement resulting in a frequency shift, and making the use of electromagnetic levitation techniques in microgravity an attractive alternative to measure thermophysical properties of liquid metals. Under microgravity conditions the magnetic field strength around a liquid droplet is significantly lower than that required to position the same specimen against earth gravity. Hence, a low magnetic field strength results in a low More >

Syh-Tsang Jenq^1,2, Yuen-Sheng Chiu²

CMC-Computers, Materials & Continua, Vol.11, No.1, pp. 33-58, 2009, DOI:10.3970/cmc.2009.011.033

Abstract Current work studies the transient hydroplaning behavior of 200 kPa inflated pneumatic radial tires with various types of tread patterns. Tires were numerically loaded with a quarter car weight of 4 kN, and then accelerated from rest rolling over a water film with a thickness of 5, 10 and 15 mm on top of a flat pavement. Tire structure is composed of outer rubber tread and inner fiber reinforcing composite layers. The Mooney-Rivlin constitutive law and the classical laminated theory (CLT) were, respectively, used to describe the mechanical behavior of rubber material and composite reinforcing… More >

I. Ueno¹, T. Konisho², T. Kawase³, T. Watanabe⁴

FDMP-Fluid Dynamics & Materials Processing, Vol.4, No.1, pp. 21-26, 2008, DOI:10.3970/fdmp.2008.004.021

Abstract The present authors carried out an experimental study with a special interest upon the dynamics of the fluid in the vicinity of the boundary line of three phases; solid-liquid-gas interface, which is so-called `contact line.' The moving droplet on the solid substrate is accompanied with the movement of the boundary line of three phases; solid-liquid-gas interface, which is so-called macroscopic 'contact line.' Existing studies have indicated there is a thin liquid film known as 'precursor film' ahead the contact line of the droplet. In the present study the precursor film was detected by applying conventional More >

Sayavur I. Bakhtiyarov¹, Dennis A. Siginer²

FDMP-Fluid Dynamics & Materials Processing, Vol.4, No.2, pp. 99-112, 2008, DOI:10.3970/fdmp.2008.004.099

Abstract Levitation of liquid bodies against gravity is a contactless confinement process appropriate for manufacturing very pure materials. A variety of levitation techniques have been developed over the last few decades, such as aerodynamic, acoustic, electrostatic, microwave, and electromagnetic levitations. More recently, a new generation of novel techniques, essentially combinations of the established primary techniques, has been successfully introduced. Examples are acoustic-electric, aerodynamic-acoustic and acoustic-electromagnetic. The purpose of this series of papers in three parts, Bakhtiyarov and Siginer (2007a,b), is to review the advances in electromagnetic levitation (EML) since its introduction as a containerless melting technique, More >

H. Payer¹, T. Haschke¹, R. Reichardt¹, G. Li², K. Graf^2,3, W. Wiechert^1,3

FDMP-Fluid Dynamics & Materials Processing, Vol.4, No.2, pp. 61-76, 2008, DOI:10.3970/fdmp.2008.004.061

Abstract Microstructured surfaces are of steadily increasing importance in a large variety of technological applications. For the purpose of quality assurance, e.g. during variation studies of experimental parameters or for comparison with results from simulations, the surface geometry must be precisely measured and described in terms of geometric parameters. An analysis tool for regularly structured surfaces is presented that performs a highly automated evaluation of surface scanning data and derives geometric quality control parameters. To demonstrate the power of the analysis tool it is exemplarily applied for the investigation of microcraters emerging after the evaporation of… More >

S. Chen^1,2, Y. Liu^1,3, B.C. Khoo⁴, X.J. Fan⁵, J.T. Fan⁶

CMES-Computer Modeling in Engineering & Sciences, Vol.19, No.3, pp. 181-196, 2007, DOI:10.3970/cmes.2007.019.181

Abstract The mesoscopic simulation for fluids flow in a square microchannel is investigated using dissipative particle dynamics. The velocity distribution for single fluid in a square channel is compared with the solutions of CFD solver, which is found to be in good agreement with each other. The no-slip boundary condition could be well held for the repulsive coefficient ranged from 9.68 to 18.0. For the same range of repulsive coefficient, various wettabilities could be obtained by changing the repulsive coefficient for binary immiscible fluids, in which the immiscible fluids are achieved by increasing the repulsive force… More >

Heng Xie¹, Seiichi Koshizuka², Yoshiaki Oka²

CMES-Computer Modeling in Engineering & Sciences, Vol.18, No.1, pp. 1-16, 2007, DOI:10.3970/cmes.2007.018.001

Abstract A model of a single liquid drop colliding on solid surface is developed based with Moving Particle Semi-implicit (MPS) method. The mathematical model involves gravity, viscosity and surface tension. The wettability between the impact liquid and the solid surface is modeled by the contact angle model and the non-slip boundary condition. The particles of the drop are divided into four types in which the model varies to simulate the liquid particles in different area. The model is validated by the comparison of the theoretical results. The complete dynamic process including the spreading, the recoiling, re-bouncing More >