Kirill Rysin^*

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.10, pp. 2235-2249, 2024, DOI:10.32604/fdmp.2024.052324 - 23 September 2024

Abstract The study of average convection in a rotating cavity subjected to modulated rotation is an interesting area for the development of both fundamental and applied science. This phenomenon finds application in the field of mass transfer and fluid flow control, relevant examples being crystal growth under reduced gravity and fluid mixing in microfluidic devices for cell cultures. In this study, the averaged flow generated by the oscillating motion of a fluid in a planar layer rotating about a horizontal axis is experimentally investigated. The boundaries of the layer are maintained at constant temperatures, while the… More >

Olga Vlasova^*

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.9, pp. 2127-2137, 2024, DOI:10.32604/fdmp.2024.051202 - 23 August 2024

Abstract The dynamics of rotating hydrodynamic systems containing phase inclusions are interesting due to the related widespread occurrence in nature and technology. The influence of external force fields on rotating systems can be used to control the dynamics of inclusions of various types. Controlling inclusions is of current interest for space technologies. In low gravity, even a slight vibration effect can lead to the appearance of a force acting on phase inclusions near a solid boundary. When vibrations are applied to multiphase hydrodynamic systems, the oscillating body intensively interacts with the fluid and introduces changes in… More >

Ivan Karpunin^*

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.6, pp. 1219-1232, 2024, DOI:10.32604/fdmp.2024.051062 - 27 June 2024

Abstract The dynamics of a solid spherical body in an oscillating liquid flow in a vertical axisymmetric channel of variable cross section is experimentally studied. It is shown that the oscillating liquid leads to the generation of intense averaged flows in each of the channel segments. The intensity and direction of these flows depend on the dimensionless oscillating frequency. In the region of studied frequencies, the dynamics of the considered body is examined when the primary vortices emerging in the flow occupy the whole region in each segment. For a fixed frequency, an increase in the… More >

Anastasia Bushueva, Olga Vlasova, Denis Polezhaev^*

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.4, pp. 847-857, 2024, DOI:10.32604/fdmp.2024.048271 - 28 March 2024

Abstract The steady flow in a Hele-Shaw cell filled with fluids with a high viscosity contrast in the presence of fluid oscillations is experimentally studied. The control of oscillatory dynamics of multiphase systems with interfaces is a challenging technological problem. We consider miscible (water and glycerol) and immiscible (water and high-viscosity silicone oil PMS-1000) fluids under subsonic oscillations perpendicular to the interface. Observations show that the interface shape depends on the amplitude and frequency of oscillations. The interface is undisturbed only in the absence of oscillations. Under small amplitudes, the interface between water and glycerol widens… More >

Victor Kozlov^1,*, Vladimir Saidakov¹, Nikolai Kozlov²

FDMP-Fluid Dynamics & Materials Processing, Vol.20, No.4, pp. 693-703, 2024, DOI:10.32604/fdmp.2024.048068 - 28 March 2024

Abstract The behavior of two immiscible low-viscosity liquids differing in density and viscosity in a vertical flat layer undergoing modulated rotation is experimentally studied. The layer has a circular axisymmetric boundary. In the absence of modulation of the rotation speed, the interphase boundary has the shape of a short axisymmetric cylinder. A new effect has been discovered, under the influence of rotation speed modulation, the interface takes on a new dynamic equilibrium state. A more viscous liquid covers the end boundaries of the layer in the form of thin films, which have the shape of round… More >

Jun Zeng¹, Fucheng Tian^1,*

The International Conference on Computational & Experimental Engineering and Sciences, Vol.27, No.2, pp. 1-1, 2023, DOI:10.32604/icces.2023.09636

Abstract Instability in dynamic fracture suppresses crack velocity from reaching theoretical limit predicted by the classical linear elastic fracture mechanics (LEFM). In thin systems, crack can accelerate to near the theoretical limiting velocity without micro-branching instability. A dynamic oscillatory instability is observed at such extreme crack speed. This sinusoidal oscillation was further found to be governed by intrinsic nonlinear scale. Using a dynamic phase-field model (PFM) with no attenuation of wave speed, we successfully reproduce the oscillations in the framework of non-linear deformation. The used PFM model based on Griffith's theory and derived from the nonconservative… More >

Zong Bi^*, Weifeng Shi, Tiewei Song

Energy Engineering, Vol.119, No.3, pp. 907-928, 2022, DOI:10.32604/ee.2022.019627 - 31 March 2022

Abstract In the marine electric power system, the marine generators will be disturbed by the large change of loads or the fault of the power system. The marine generators usually installed power system stabilizers to damp power system oscillations through the excitation control. This paper proposes a novel method to obtain optimal parameter values for Power System Stabilizer (PSS) to suppress low-frequency oscillations in the marine electric power system. In this paper, a newly developed immune clone selection algorithm was improved from the three aspects of the adaptive incentive degree, vaccination, and adaptive mutation strategies. Firstly,… More >

Aleksandr Shiryaev^*

FDMP-Fluid Dynamics & Materials Processing, Vol.16, No.4, pp. 761-771, 2020, DOI:10.32604/fdmp.2020.09010 - 11 August 2020

Abstract The problem relating to the small-amplitude free capillary oscillations of an encapsulated spherical drop is solved theoretically in the framework of asymptotic methods. Liquids are supposed to be inviscid and immiscible. The formulas derived are presented for different parameters of the inner and outer liquids, including densities, thickness of the outer liquid layer, and the surface and interfacial tension coefficients. The frequencies of oscillation of the encapsulated drop are studied in relation to several “modes” which can effectively be determined in experiments by photo and video analysis. The results are presented in terms of oscillation More >

Mikael A. Langthjem¹, Masami Nakano²

CMES-Computer Modeling in Engineering & Sciences, Vol.96, No.4, pp. 227-241, 2013, DOI:10.3970/cmes.2013.096.227

Abstract This paper is concerned with a mathematical model of a simple axisymmetric silencer-like model, consisting of a hole-tone feedback system equipped with a tailpipe. The unstable shear layer is modeled via a discrete vortex method, based on axisymmetric vortex rings. The aeroacoustic model is based on the Powell- Howe theory of vortex sound. Boundary integrals are discretized via the boundary element method; but the tailpipe is represented by the exact (one-dimensional) solution. It is demonstrated though numerical examples that this numerical model can display lock-in of the self-sustained flow oscillations to the resonant acoustic oscillations. More >

Hong-Hua Dai^1,2, Matt Schnoor², Satya N. Atluri²

CMES-Computer Modeling in Engineering & Sciences, Vol.84, No.5, pp. 459-498, 2012, DOI:10.3970/cmes.2012.084.459

Abstract In this study, the harmonic and 1/3 subharmonic oscillations of a single degree of freedom Duffing oscillator with large nonlinearity and large damping are investigated by using a simple point collocation method applied in the time domain over a period of the periodic solution. The relationship between the proposed collocation method and the high dimensional harmonic balance method (HDHB), proposed earlier by Thomas, Dowell, and Hall (2002), is explored. We demonstrate that the HDHB is not a kind of "harmonic balance method" but essentially a cumbersome version of the collocation method. In using the collocation method,… More >