Response of a Liquid Bridge With Rotationally Excited Bottom

1992 ◽  
Vol 59 (1) ◽  
pp. 191-195 ◽  
Author(s):  
Helmut F. Bauer
Keyword(s):  
Free Surface ◽  
Velocity Distribution ◽  
Liquid Bridge ◽  
Transient Behavior ◽  
Liquid Column ◽  
Semi Empirical

The response of a cylindrical liquid column consisting of an incompressible and frictionless liquid has been investigated for a pitching bridge bottom. The response of the free surface and velocity distribution has been determined and numerically evaluated. In addition, the transient behavior of the column has been treated. Since for nonviscous liquid the response exhibits at the resonances singularity, a semi-empirical damping was introduced in the resonance terms. Its magnitude has to be determined by experiments.

Super Accelerated Flow in Diverging Conical Pipes

2011 ◽  
Vol 110-116 ◽  
pp. 880-885
Author(s):  
G.J. Gutierrez ◽  
A. López Villa ◽  
A. Torres ◽  
S. Peralta ◽  
C. A. Vargas
Keyword(s):  
Free Surface ◽  
Free Fall ◽  
Liquid Column ◽  
Dimensional Model ◽  
One Dimensional ◽  
Low Viscosity ◽  
Accelerated Flow ◽  
Theoretical Results

The motion of the upper free surface of a liquid column released from rest in a vertical, conical container is analyzed theoretically and experimentally. An inviscid, one-dimensional model, for a slightly expanding pipe's radius, describes how the recently reported super free fall of liquids occurs in liquids of very low viscosity. Experiments agree with the theoretical results.

scholarly journals The effect of uniform magnetic field on spatial-temporal evolution of thermocapillary convection with the silicon oil based ferrofluid

2020 ◽  
Vol 24 (6 Part B) ◽  
pp. 4159-4171
Author(s):  
Shuo Yang ◽  
Rui Ma ◽  
Qiaosheng Deng ◽  
Guofeng Wang ◽  
Yu Gao ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Free Surface ◽  
Transverse Magnetic Field ◽  
Liquid Bridge ◽  
Thermocapillary Convection ◽  
Surface Deformation ◽  
Axial Magnetic Field ◽  
Transverse Magnetic ◽  
Surface Flow ◽  
Silicon Oil

A uniform axial or transverse magnetic field is applied on the silicon oil based ferrofluid of high Prandtl number fluid (Pr ? 111.67), and the effect of magnetic field on the thermocapillary convection is investigated. It is shown that the location of vortex core of thermocapillary convection is mainly near the free surface of liquid bridge due to the inhibition of the axial magnetic field. A velocity stagnation region is formed inside the liquid bridge under the axial magnetic field (B = 0.3-0.5 T). The disturbance of bulk reflux and surface flow is suppressed by the increasing axial magnetic field. There is a dynamic response of free surface deformation to the axial magnetic field, and then the contact angle variation of the free surface at the hot corner is as following, ?hot, B = 0.5 T = 83.34? > ?hot, B = 0.3 T = 72.16? > > ?hot,B = 0.1 T = 54.21? > ?hot, B = 0 T = 43.33?. The results show that temperature distribution near the free surface is less and less affected by thermocapillary convection with the increasing magnetic field, and it presents a characteristic of heat-conduction. In addition, the transverse magnetic field does not realize the fundamental inhibition for thermocapillary convection, but it transfers the influence of thermocapillary convection to the free surface.

scholarly journals Experimental Characterization of the Hydraulic Jump Profile and Velocity Distribution in a Stilling Basin Physical Model

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1758
Author(s):  
Juan Macián-Pérez ◽  
Francisco Vallés-Morán ◽  
Santiago Sánchez-Gómez ◽  
Marco De-Rossi-Estrada ◽  
Rafael García-Bartual
Keyword(s):  
Free Surface ◽  
Energy Dissipation ◽  
Velocity Distribution ◽  
Physical Model ◽  
Hydraulic Jump ◽  
Surface Profile ◽  
Air Entrainment ◽  
Stilling Basin ◽  
Free Surface Profile ◽  
Stilling Basins

The study of the hydraulic jump developed in stilling basins is complex to a high degree due to the intense velocity and pressure fluctuations and the significant air entrainment. It is this complexity, bound to the practical interest in stilling basins for energy dissipation purposes, which brings the importance of physical modeling into the spotlight. However, despite the importance of stilling basins in engineering, bibliographic studies have traditionally focused on the classical hydraulic jump. Therefore, the objective of this research was to study the characteristics of the hydraulic jump in a typified USBR II stilling basin, through a physical model. The free surface profile and the velocity distribution of the hydraulic jump developed within this structure were analyzed in the model. To this end, an experimental campaign was carried out, assessing the performance of both, innovative techniques such as the time-of-flight camera and traditional instrumentation like the Pitot tube. The results showed a satisfactory representation of the free surface profile and the velocity distribution, despite some discussed limitations. Furthermore, the instrumentation employed revealed the important influence of the energy dissipation devices on the flow properties. In particular, relevant differences were found for the hydraulic jump shape and the maximum velocity positions within the measured vertical profiles, when compared to classical hydraulic jumps.

Hydrodynamic Forces on a Marine Riser: A Velocity-Potential Method

1982 ◽  
Vol 104 (1) ◽  
pp. 53-57 ◽  
Author(s):  
J. S. Chung
Keyword(s):  
Free Surface ◽  
Velocity Potential ◽  
Potential Method ◽  
Hydrodynamic Forces ◽  
Marine Riser ◽  
Morison Equation ◽  
Wave Damping ◽  
Drag Forces ◽  
Vessel Motion ◽  
Semi Empirical

A linear equation is mathematically derived for hydrodynamic forces on a marine riser under effects of free surface and floating-vessel motion using a velocity-potential method. It accounts for inertia and wave damping forces, including the force caused by riser motion, and empirically includes the drag force caused by viscosity. The equation, when reduced to a simpler form, is basically identical to the semi-empirical Morison equation for the inertia and drag forces. Theoretical validity of the simpler equation and the Morison equation is discussed. Previously, practical, semi-empirical force equations on the riser have been suggested, ignoring the effects of the free surface and the wave damping. The equations in current practice are compared with the present simpler equation.

scholarly journals Study on the internal two-phase flow of the inverted-umbrella aerator

2019 ◽  
Vol 11 (8) ◽  
pp. 168781401987173 ◽  
Author(s):  
Liang Dong ◽  
Jiawei Liu ◽  
Houlin Liu ◽  
Cui Dai ◽  
Dmitry Vladimirovich Gradov
Keyword(s):  
Free Surface ◽  
Velocity Distribution ◽  
Surface Deformation ◽  
Two Phase Flow ◽  
Back Surface ◽  
High Speed Photography ◽  
Aeration Tank ◽  
Phase Flow ◽  
Two Phase ◽  
Radial Profiles

In order to reveal the gas–liquid two-phase flow pattern of inverted-umbrella aerator, the high-speed photography technology, particle image velocimetry, and Volume of Fluid model are employed to capture the free-surface dynamics and velocity distribution. The Computational Fluid Dynamics simulations are validated by experimental data and the results are in good agreement with experiment. The simulation results of flow field, streamline distribution, velocity distribution, free-surface deformation, and turbulence kinetic energy are analyzed at in time and at radial profiles sampled at several vertical positions. Back surface of each blade revealed the area of low-pressure, which can drag air into water directly from surface and thus enhance liquid aeration and oxygenation capacity. Lifting capacity of the inverted-umbrella aerator is enough to get the liquid at the bottom of the aeration tank accelerated toward liquid surface generating the hydraulic jump. As a result, liquid phase splashes capture portions of air promoting aeration of the solution. A clear circulation whirlpool is formed during the process. The circulation whirlpool starts at the bottom of the impeller moving upward along the plate until the outer edge of the impeller, which is close to the free surface. The circulation whirlpool indicates that the inverted-umbrella aerator plays a significant role in shallow aeration. The turbulence intensity created by the impeller gradually reduces with depth. The position ( z = 0.65 H) is the watershed in the tank. The oxygen mass transfer mainly occurs in the layer above watershed.

Generation Mechanism of Liquid Column during the Burst of a Rising Bubble near a Free Surface

2010 ◽  
Vol 27 (5) ◽  
pp. 054703 ◽  
Author(s):  
Wang Han ◽  
Zhang Zhen-Yu ◽  
Yang Yong-Ming ◽  
Zhang Hui-Sheng
Keyword(s):  
Free Surface ◽  
Liquid Column ◽  
Generation Mechanism ◽  
Rising Bubble
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