The Experts below are selected from a list of 78 Experts worldwide ranked by ideXlab platform
Maklakov D. - One of the best experts on this subject based on the ideXlab platform.
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Stratified Laminar Flows in Inclined Pipes
2020Co-Authors: Maklakov D.Abstract:© 2019, Allerton Press, Inc. We investigate stratified Laminar Flows of a two-phase fluid in inclined circular pipes for the case when the interface is a circular arc orthogonal to the pipe wall. The velocity field is obtained in the form of the sum of an elementary function and a one-dimensional integral of an elementary function
Urmancheev S. F. - One of the best experts on this subject based on the ideXlab platform.
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On stability of thermoviscous liquids Laminar flow
Тюменский государственный университет, 2020Co-Authors: Низамова, А. Д., Киреев, В. Н., Урманчеев, С. Ф., Nizamova A. D., Kireev V. N., Urmancheev S. F.Abstract:Рассмотрена задача о влиянии температурной зависимости вязкости жидкости на устойчивость ламинарного режима течения в плоском канале с неоднородным температурным полем. Получены аналитические выражения, описывающие профили скорости в невозмущенном состоянии для линейной и экспоненциальной зависимостей вязкости от температуры. Получена система двух обыкновенных дифференциальных уравнений для амплитуд возмущений скорости и температуры, которая в случае изотермического течения может быть сведена к классическому уравнению Орра-Зоммерфельда. Численно исследованы спектры собственных значений для ламинарных течений с различными зависимостями вязкости жидкости от температуры. Обнаружены значительные различия между спектрами собственных значений для течения термовязкой жидкости и жидкости с постоянной вязкостью. Показано, что учет температурной зависимости вязкости жидкости оказывает существенное влияние на устойчивость ламинарного течения жидкостиThe problem of the influence of temperature dependence of viscosity on stability of Laminar liquid Flows in a plane channel with non-uniform temperature field is considered. The analytical expressions of undisturbed velocity profiles for plane non-isothermal fluid Flows with linear and exponential dependences viscosity on temperature have been derived. The system of two ordinary differential equations for perturbation amplitudes of velocity and temperature has been developed. In the case of isothermal flow, this system of ODE can be reduced to the classical Orr-Sommerfeld equation. The spectra of eigenvalues for Laminar Flows with different temperature dependences of viscosity have been studied numerically. The considerable differences between the spectra of eigenvalues for the flow of thermoviscous fluid and fluid with constant viscosity are discovered. Consideration of the temperature dependence on fluid viscosity affecting considerably stability of Laminar Flows is shown
Helffe Ernard - One of the best experts on this subject based on the ideXlab platform.
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On the stability of Laminar Flows between plates
2020Co-Authors: Almog Yaniv, Helffe ErnardAbstract:Consider a two-dimensional Laminar flow between two plates, so that $(x_1,x_2)\in {\mathbb R} \times[-1,1]$, given by ${\mathbf v}(x_1,x_2)=(U(x_2),0)$, where $U\in C^4([-1,1])$ satisfies $U^\prime\neq0$ in $[-1,1]$. We prove that the flow is linearly stable in the large Reynolds number limit, in two different cases: $\bullet$ $\sup_{x\in[-1,1]} |U"(x)| + \sup_{x\in[-1,1]} |U"(x)| \ll \min_{x\in[-1,1]}|U^\prime(x)|$ (nearly Couette Flows), $\bullet$ $U^{\prime\prime}\neq0$ in $[-1,1]$. We assume either no-slip or fixed traction force conditions on the plates, and an arbitrary large (but much smaller than the Reynolds number) period in the $x_1$ direction
Низамова, А. Д. - One of the best experts on this subject based on the ideXlab platform.
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On stability of thermoviscous liquids Laminar flow
Тюменский государственный университет, 2020Co-Authors: Низамова, А. Д., Киреев, В. Н., Урманчеев, С. Ф., Nizamova A. D., Kireev V. N., Urmancheev S. F.Abstract:Рассмотрена задача о влиянии температурной зависимости вязкости жидкости на устойчивость ламинарного режима течения в плоском канале с неоднородным температурным полем. Получены аналитические выражения, описывающие профили скорости в невозмущенном состоянии для линейной и экспоненциальной зависимостей вязкости от температуры. Получена система двух обыкновенных дифференциальных уравнений для амплитуд возмущений скорости и температуры, которая в случае изотермического течения может быть сведена к классическому уравнению Орра-Зоммерфельда. Численно исследованы спектры собственных значений для ламинарных течений с различными зависимостями вязкости жидкости от температуры. Обнаружены значительные различия между спектрами собственных значений для течения термовязкой жидкости и жидкости с постоянной вязкостью. Показано, что учет температурной зависимости вязкости жидкости оказывает существенное влияние на устойчивость ламинарного течения жидкостиThe problem of the influence of temperature dependence of viscosity on stability of Laminar liquid Flows in a plane channel with non-uniform temperature field is considered. The analytical expressions of undisturbed velocity profiles for plane non-isothermal fluid Flows with linear and exponential dependences viscosity on temperature have been derived. The system of two ordinary differential equations for perturbation amplitudes of velocity and temperature has been developed. In the case of isothermal flow, this system of ODE can be reduced to the classical Orr-Sommerfeld equation. The spectra of eigenvalues for Laminar Flows with different temperature dependences of viscosity have been studied numerically. The considerable differences between the spectra of eigenvalues for the flow of thermoviscous fluid and fluid with constant viscosity are discovered. Consideration of the temperature dependence on fluid viscosity affecting considerably stability of Laminar Flows is shown
Su Chao - One of the best experts on this subject based on the ideXlab platform.
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Bubbly and Buoyant Particle-Laden Turbulent Flows
'Annual Reviews', 2020Co-Authors: Mathai Varghese, Lohse Detlef, Su ChaoAbstract:Fluid turbulence is commonly associated with stronger drag, greater heat transfer, and more efficient mixing than in Laminar Flows. In many natural and industrial settings, turbulent liquid Flows contain suspensions of dispersed bubbles and light particles. Recently, much attention has been devoted to understanding the behavior and underlying physics of such Flows by use of both experiments and high-resolution direct numerical simulations. This review summarizes our present understanding of various phenomenological aspects of bubbly and buoyant particle-laden turbulent Flows. We begin by discussing different dynamical regimes, including those of crossing trajectories and wake-induced oscillations of rising particles, and regimes in which bubbles and particles preferentially accumulate near walls or within vortical structures. We then address how certain paradigmatic turbulent Flows, such as homogeneous isotropic turbulence, channel flow, Taylor-Couette turbulence, and thermally driven turbulence, are modified by the presence of these dispersed bubbles and buoyant particles. We end with a list of summary points and future research questions.Comment: 29 pages, 14 figure
