scholarly journals Исследование реакции поверхности жидкости на импульсное воздействие наклонной газовой струи при малых числах Рэйнольдса

2022 ◽  
Vol 92 (2) ◽  
pp. 216
Author(s):  
А.П. Савенков ◽  
В.А. Сычёв
Keyword(s):  
Drag Force ◽  
Liquid Surface ◽  
Dynamic Properties ◽  
Liquid System ◽  
Gas Jet ◽  
Viscous Drag ◽  
Phase System ◽  
Two Phase ◽  
Automatic Control Theory ◽  
Viscous Drag Force

A mathematical description of the motion of a cavity on the liquid surface under an oblique action of a gas jet is obtained using the well-known expressions for the movement of a gas bubble in a liquid. The boundary of the viscous drag force domination over the form drag force is determined. The impingement of the gas jet on the liquid surface is considered as a dynamic object of the automatic control theory. It is found that the dynamic properties of the two-phase system "gas jet - liquid" are described by the integrator equations. Using a specially designed setup, the transient response of the "gas jet - liquid" system were experimentally obtained for the aerodynamic action at angles of 20º and 50º to the surfaces of liquids with the viscosities of 0.71 and 26.1 Pa•s (Reynolds number Re < 2). The research results are necessary for the analysis of the non-contact aerodynamic method of liquid viscosity measurements.

The numerical study of viscous drag force influence on low-frequency surge motion of a semi-submersible in storm sea states

2020 ◽  
Vol 213 ◽  
pp. 107511 ◽  
Author(s):  
Shan Ma ◽  
De-kang Xu ◽  
Wen-yang Duan ◽  
Ji-kang Chen ◽  
Kang-ping Liao ◽  
...  
Keyword(s):  
Drag Force ◽  
Numerical Study ◽  
Low Frequency ◽  
Viscous Drag ◽  
Viscous Drag Force

scholarly journals Thermodynamics of phase equilibrium in solid-liquid and solid-gas systems

2021 ◽  
Vol 83 (1) ◽  
pp. 30-35
Author(s):  
Y. I. Shishatskii ◽  
A. A. Derkanosova ◽  
S. A. Tolstov
Keyword(s):  
Driving Force ◽  
Cheese Whey ◽  
Extraction Process ◽  
Liquid System ◽  
Average Concentration ◽  
Phase System ◽  
Gibbs Equation ◽  
Two Phase ◽  
Thermodynamic Potentials ◽  
Solid Liquid

The thermodynamic equilibrium of a two-phase system is described by the Gibbs equation, which includes state parameters. On the basis of the Gibbs equation and the combined equation of the first and second laws of thermodynamics, thermodynamic potentials are written: internal energy, enthalpy and Gibbs free energy. If the two phases are in equilibrium, then the temperatures, pressures and chemical potentials of these phases are equal to each other. Equalities express the conditions of thermal and mechanical equilibrium, as well as the condition for the absence of a driving force for the transfer of a component across the interface. For a two-phase system, the Gibbs-Duhem equation connects the volume and entropy of 1 mole of the mixture, the content of any component, expressed in mole fractions. Extraction from lupine particles with cheese whey (solid-liquid system) is considered. The driving force of the extraction process in the solid-liquid system is the difference between the concentration of the solvent at the surface of the solid C and its average concentration C0 in the bulk of the solution. The concentration at the interface is usually taken to be equal to the concentration of a saturated solution of Cn, since equilibrium is established rather quickly near the surface of a solid. Then the driving force of the process is expressed as Cn – C0. A curve for the extraction of extractives from lupine with cheese whey was plotted by superimposing low-frequency mechanical vibrations.

The viscous drag force on a spherical bubble with a time-dependent radius

1998 ◽  
Vol 10 (3) ◽  
pp. 550-554 ◽  
Author(s):  
Jacques Magnaudet ◽  
Dominique Legendre
Keyword(s):  
Drag Force ◽  
Time Dependent ◽  
Viscous Drag ◽  
Spherical Bubble ◽  
Viscous Drag Force

Structures of a Magnetorheological Fluid

2001 ◽  
Vol 15 (06n07) ◽  
pp. 851-858 ◽  
Author(s):  
G. L. Gulley ◽  
R. Tao
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Drag Force ◽  
Liquid State ◽  
Magnetorheological Fluid ◽  
Viscous Drag ◽  
Viscous Drag Force ◽  
Brownian Force ◽  
Dynamics Simulations ◽  
Two Parameters

Molecular dynamics simulations were carried out to find the underlying structures of a Magnetorheological (MR) fluid while taking into account dipolar forces, viscous drag, and the Brownian force. Three different structures were found: the bct lattice, chains, and a liquid state. The conditions under which these structures are found is based on two parameters A and B which are the ratios of the dipolar force to the viscous drag force and the Brownian force to the dipolar force respectively.

Velocity Measurements in Microscopic Two-Phase Flows by Means of Micro PIV

2008 ◽  
Author(s):  
Ulrich Miessner ◽  
Ralph Lindken ◽  
Jerry Westerweel
Keyword(s):  
Liquid System ◽  
Index Of Refraction ◽  
Refractive Indices ◽  
Phase System ◽  
Velocity Measurements ◽  
Two Phase Flows ◽  
Two Phase ◽  
Spherical Droplet ◽  
Micro Particle Image Velocimetry ◽  
Micro Piv

This article examines the velocity distributions of microscopic liquid-liquid two-phase flows by means of micro particle image velocimetry (micro-PIV). Aqueous droplets are dispersed into an oil bulk at the T-junction of a micro fluidic Polydimethylsiloxane (PDMS) device. The channel geometry is rectangular (H: 100μm, W: 100μm). The flow is pressure driven. Tracer particles (D: 0.5–1.2μm) are added to either phase, enabling simultaneous measurements in both phases. However, the use of immiscible liquids causes optical disturbances due to a difference in refractive indices of the two liquids and due to a curved interface geometry. Particle images are thus imaged in a distorted field of view. The results of a PIV analysis will be inaccurate in scaling as well as in location of the velocity vectors — depending on the mismatch of the refractive index. We present a basic analysis on the effect of mismatched refractive indices on the precision of the velocity measurements. The estimation is based on Snell’s law and the simplified geometry of a spherical droplet. Furthermore, we propose a method to match not only the index of refraction accurately but also to leave one additional degree of freedom to set an additional property of the liquid-liquid system, e.g. viscosity ratio or density ratio. The latter ensures that properties of the modified liquid-liquid system are close to those of the non-modified two-phase system. The findings of this study are part of the design of a Lab-on-a-Chip device. It performs a DNA analysis in an online quality control application. The miniaturization of a two-phase flow combines the benefits of confined sample compartments (i.e. droplets) with the easy-to-control process parameters of a miniaturized device (e.g. temperature, pressure). Thus band broadening of the sample by Taylor-Aris dispersion is avoided and the processes can be set accurately.

Dark Matter: Could It Be Vacuum Viscosity?

2020 ◽  
Vol 13 (1) ◽  
pp. 47-57
Keyword(s):  
Dark Matter ◽  
Simple Model ◽  
Drag Force ◽  
Spiral Galaxies ◽  
Viscous Drag ◽  
Rotation Curves ◽  
The Galaxy ◽  
Viscous Drag Force ◽  
Matter Effect ◽  
Good Agreement

We test a hypothesis that stars located away from the center of the galaxy, moving under the effect of an emergent viscous drag force perpendicular to their velocities, might exhibit the behavior observed in the rotation curves of the spiral galaxies. We construct a simple model for such an assumption, then by using simple fitting technique, we are able to produce the rotation curves for a sample of 18 spiral galaxies. Results show good agreement with the observed rotation curves. The applicability of our hypothesis suggests that an emergent drag force perpendicular to the velocity of the stars might be the cause of the apparent dark matter effect.

On the Problem of “Two-Phase” Activated Sludge

1991 ◽  
Vol 24 (7) ◽  
pp. 59-64 ◽  
Author(s):  
R. W. Szetela
Keyword(s):  
Activated Sludge ◽  
Single Phase ◽  
Phase System ◽  
Two Phase ◽  
Wastewater Treatment Process ◽  
Sludge Stabilization ◽  
Technological Advantage ◽  
In Series ◽  
State Models ◽  
Activated Sludge Systems

Steady-state models are presented to describe the wastewater treatment process in two activated sludge systems. One of these makes use of a single complete-mix reactor; the other one involves two complete-mix reactors arranged in series. The in-series system is equivalent to what is known as the “two-phase” activated sludge, a concept which is now being launched throughout Poland in conjunction with the PROMLECZ technology under implementation. Analysis of the mathematical models has revealed the following: (1) treatment efficiency, excess sludge production, energy consumption, and the degree of sludge stabilization are identical in the two systems; (2) there exists a technological equivalence of “two-phase” sludge with “single-phase” sludge; (3) the “two-phase” system has no technological advantage over the “single-phase” system.

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