F. Mechighel^1,2, M. El Ganaoui¹, M. Kadja², B. Pateyron³, S. Dost⁴

FDMP-Fluid Dynamics & Materials Processing, Vol.5, No.4, pp. 313-330, 2009, DOI:10.3970/fdmp.2009.005.313

Abstract A numerical study has been carried out to investigate the three-dimen -sional buoyant flow in a parallelepiped box heated from below and partially from the two sidewalls (a configuration commonly used for solidification problems and crystal growth systems). Attention has been paid, in particular, to phenomena of symmetry breaking and transition to unsteady non-symmetric convection for a low Prandtl number fluid (Pr=0.01). The influence of an applied horizontal magnetic field on the stability properties of the flow has been also considered. Results obtained may be summarized as follows: In the absence of magnetic field and 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 >

H. Elnaiem¹, D. Casimir¹, P. Misra¹, S.M. Gatica^1,2

CMC-Computers, Materials & Continua, Vol.14, No.1, pp. 23-34, 2009, DOI:10.3970/cmc.2009.014.023

Abstract Nanobubbles have been found to form at the interface of water and solid surfaces. We examine the conditions for such bubbles to form and estimate the pressure inside the bubble based on thermodynamic considerations. Using a simple model we calculate the contact angle for a wide range of temperatures and hypothetical substrates possessing a continuous range of strengths. We show that as the temperature increases the shape of a bubble changes continuously from a spherical cap with low curvature to a complete sphere. An equivalent effect results from either increasing the strength of the solid More >

D.P.Mondal¹, S.Das¹, Anshul Badkul¹, Nidhi Jha¹

CMC-Computers, Materials & Continua, Vol.13, No.2, pp. 115-134, 2009, DOI:10.3970/cmc.2009.013.115

Abstract The cooling effect by evaporative liquid is modeled by considering that heat is transferred from the system to the surrounding due to evaporation of liquid through the pores present in the medium. The variation of cooling rate with cell size, volume fraction of pores and physical conditions has been analyzed. The model demonstrates that it increases with increase in thickness of the foam slab and with increase in velocity of air. It is also observed that cooling effect decreases with decrease in volume fraction of porosity and with increase in relative density, cell size, thermal More >

LUIS A. MROGINSKI*, PEDRO A. SANSBERRO, ADRIANA M. SCOCCHI, CLAUDIA LUNA, HEBE Y. REY

BIOCELL, Vol.32, No.1, pp. 33-39, 2008, DOI:10.32604/biocell.2008.32.033

Abstract Tropical Ilex species have recalcitrant seeds. This work describes experiments demonstrating the feasibility of long-term conservation of Ilex brasiliensis, I. brevicuspis, I. dumosa, I. intergerrima, I. paraguariensis, I. pseudoboxus, I. taubertiana, and I. theezans through cryopreservation of zygotic rudimentary embryos at the heart developmental stage. The embryos were aseptically removed from the seeds and precultured (7 days) in the dark, at 27± 2ºC on solidified (0.8% agar) 1/4MS medium, [consisting of quarterstrength salts and vitamins of Murashige and Skoog (1962) medium] with 3% sucrose and 0.1 mg/l Zeatin. The embryos were then encapsulated in 3% calcium alginate beads… More >

Jong-Kook Cha¹, Jin-Rae Cho¹

The International Conference on Computational & Experimental Engineering and Sciences, Vol.7, No.3, pp. 129-134, 2008, DOI:10.3970/icces.2008.007.129

Abstract Sloshing flow is formulated based on the linearized potential flow theory, while an artificial damping term is employed into the kinematic free-surface condition to reflect the eminent dissipation effect in resonant sloshing. Through the numerical analysis of sloshing frequency response with respect to the number, location and opening width of baffle, the sloshing damping characteristics by baffle are parametrically investigated. More >

A.A. Ivanova¹, V.G. Kozlov^1,2,3, D.A. Polezhaev¹, D. Pareau³, M. Stambouli³

FDMP-Fluid Dynamics & Materials Processing, Vol.4, No.3, pp. 211-220, 2008, DOI:10.3970/fdmp.2008.004.211

Abstract The problem for the optimization of mass-transfer on the interface of two immiscible liquids by means of vibrational hydromechanics is studied experimentally. A new vibrational cell of Lewis's type expressly conceived for such purposes is described. Flow is generated by activators in the form of disks inducing translational axial oscillations near the opposite end faces of the cavity. It is shown that such vibrating disks can lead to the onset of a large-scale toroidal whirlwind effectively mixing the liquid throughout the volume. According to the experiments, in particular, axisymmetrical radial flows are generated on both More >

V. Shevtsova^1,2, A. Mialdun¹, C. Ferrera^1,4, M. Ermakov^3,4, J. M. Montanero⁴

FDMP-Fluid Dynamics & Materials Processing, Vol.4, No.1, pp. 43-54, 2008, DOI:10.3970/fdmp.2008.004.043

Abstract Dynamic free surface deformations induced by buoyant and thermocapillary convection in liquid bridges of 5cSt silicone oil are studied experimentally and numerically. The experiments are performed in ground conditions and static deformation is unavoidable. Convective motion starts in the liquid bridge as soon as ΔT ≠ 0 and initially leads to a stationary dynamic deformation of the free surface. Oscillatory motion starts at a critical value of ΔT and causes oscillations of the interface. The final supercritical shape of the free surface is a result of the static shape with superimposed subcritical stationary and oscillatory dynamic deformations. More >

A. A. Nepomnyashchy^1,2, I. B. Simanovskii¹

FDMP-Fluid Dynamics & Materials Processing, Vol.4, No.3, pp. 185-198, 2008, DOI:10.3970/fdmp.2008.004.185

Abstract The development of instabilities under the joint action of the van der Waals forces and Marangoni stresses in a two-layer film on a heated or cooled substrate is considered. It is found that heating from below leads to the acceleration of the decomposition, decrease of the characteristic lateral size of structures, and the increase of the droplets heights. Heating from above leads to slowing down the instability rate and eventually to a complete suppression of the instability. More >

A. Ovcharova¹, N.Stankous²

FDMP-Fluid Dynamics & Materials Processing, Vol.3, No.4, pp. 349-356, 2007, DOI:10.3970/fdmp.2007.003.349

Abstract We consider a deformation of a thin film which is hanging between two solid flat walls under thermal load action. A two-dimensional model is applied to describe the motion of thin layers of viscous nonisothermal liquid under microgravity conditions. The model is based on the Navier-Stokes equations. A numerical analysis of the influence of thermal loads on the deformation and break of freely hanging thin films has been carried out. The mutual influence of capillary and thermo-capillary forces on thin film free surface position has been shown. The results of model problem solutions are presented. More >