scholarly journals Numerical and experimental investigation into the dynamics of a bubble-free-surface system

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
N. Bempedelis ◽  
J. Zhou ◽  
M. Andersson ◽  
Y. Ventikos
Keyword(s):  
Experimental Investigation ◽  
Free Surface ◽  
Surface System

Base-Vented Hydrofoils of Finite Span Under a Free Surface: An Experimental Investigation

1984 ◽  
Vol 28 (02) ◽  
pp. 90-106
Author(s):  
Jacques Verron ◽  
Jean-Marie Michel
Keyword(s):  
Experimental Investigation ◽  
Free Surface ◽  
Flow Rate ◽  
Cavity Length ◽  
Three Dimensional ◽  
Leading Edge ◽  
Pulsation Frequency ◽  
Cavity Pressure ◽  
Air Flow Rate ◽  
Cavity Configuration

Experimental results are given concerning the behavior of the flow around three-dimensional base-vented hydrofoils with wetted upper side. The influence of planform is given particular consideration so that the sections of the foils are simple wedges with rounded noses. Results concern cavity configuration, the relation between the air flow rate and cavity pressure, leading-edge cavitation, cavity length, pulsation frequency, and force coefficients.

Experimental Investigation of Free Surface Gradients in a 90° Angled Asymmetrical Open Channel Confluence

2018 ◽  
pp. 803-819 ◽  
Author(s):  
Stéphan Creëlle ◽  
Lukas Engelen ◽  
Laurent Schindfessel ◽  
Pedro X. Ramos ◽  
Tom De Mulder
Keyword(s):  
Experimental Investigation ◽  
Free Surface ◽  
Open Channel ◽  
Channel Confluence

An Experimental Investigation of Free Surface Transport, Bifurcation, and Adhesion Phenomena as Related to a Hollow Glass Ampule and a Metallic Conductor

1992 ◽  
Vol 114 (3) ◽  
pp. 743-751 ◽  
Author(s):  
S. C. Chen ◽  
K. Vafai
Keyword(s):  
Experimental Investigation ◽  
Free Surface ◽  
Surface Transport ◽  
Fiber Production ◽  
Hollow Glass ◽  
Physical Mechanisms ◽  
Glass Ampule ◽  
Glass Processing ◽  
Metallic Conductor ◽  
Basic Understanding

An experimental investigation of free surface transport and subsequent bifurcation and adhesion for a hollow glass ampule is presented in this work. Detailed phenomenological features of the process are displayed and discussed. This experimental investigation, which is generic in nature, provides the much needed phenomenological information on free surface transport, glass processing as related to optical fiber production, and glass-to-metal sealing processes. Detailed images of the actual sealing process provide valuable information on identifying and isolating the key regimes in the process and mapping out process defects, and contribute to a basic understanding of the physical mechanisms involved in the sealing process.

Experimental Investigation of the Flow With a Free Surface in an Impulsively Rotating Cylinder

1991 ◽  
Vol 113 (2) ◽  
pp. 245-249 ◽  
Author(s):  
Sangmin Choi ◽  
Jae Won Kim ◽  
Jae Min Hyun
Keyword(s):  
Image Processing ◽  
Experimental Investigation ◽  
Free Surface ◽  
Processing Technique ◽  
Velocity Shear ◽  
Image Processing Technique ◽  
Laser Doppler Velocimeter ◽  
Numerical Predictions ◽  
Shear Front ◽  
Propagating Shear

An experimental investigation was made of the impulsive spin-up from rest of a liquid in a partially filled cylindrical container. The main impetus was placed on delineating the effects of the presence of a free surface on the transient development of flow. Of particular interest were the situations in which the free surface intersected either or both of the endwall disks during the course of spin-up. Extensive flow visualizations were carried out by using suspended metal particles. An image processing technique was utilized to determine accurately the propagating velocity shear front as well as the time-dependent free surface contour. Precise measurements of the fluids velocities were obtained by using a laser Doppler velocimeter. The transient velocity profiles were mapped out, and they were found to be in satisfactory agreement with the predictions based on the simplified analysis. The radial location, Rs(t), of the propagating shear front was measured by applying the image processing technique to the visualized azimuthal flow field. The experimental data were found to be consistent with the numerical predictions.

Experimental Investigation of Single-Phase Micro Jets Impingement Cooling for Electronic Applications

2003 ◽  
Author(s):  
Matteo Fabbri ◽  
Shanjuan Jiang ◽  
Vijay K. Dhir
Keyword(s):  
Experimental Data ◽  
Experimental Investigation ◽  
Reynolds Number ◽  
Free Surface ◽  
Single Phase ◽  
Impinging Jets ◽  
Heat Fluxes ◽  
Number Range ◽  
Impingement Cooling ◽  
Circular Arrays

Impinging jets for cooling of electronic equipment have been used by many researchers. Only few studies using arrays composed of a small number of jets are available in the literature. When very small jet diameters are used, the jet Reynolds number becomes quite small and no data are available for Reynolds number values below 500. In this work attention has been focused on circular arrays of free surface micro jets. Experiments were conducted by employing three jet pitches, 1, 2 and 3 mm and four jet diameters 50, 100, 150 and 250 μm and two different fluids, DI water and FC 40. The jet Reynolds number range was varied between 90 and 2000 while the Prandtl number varied from 6 to 84. Heat fluxes as high as 250 W/cm2 could be removed when water was utilized. Experimental data have been correlated within ±20%.

Experimental Investigation into the Instability of an Over-Hung Rigid Centrifuge Rotor Partially Filled With Fluid

2002 ◽  
Vol 124 (4) ◽  
pp. 483-491 ◽  
Author(s):  
Zhu Changsheng
Keyword(s):  
Experimental Investigation ◽  
Free Surface ◽  
Upper Bound ◽  
Dynamical Behavior ◽  
Rotor System ◽  
Unstable Region ◽  
Fill Ratio ◽  
Rotor Imbalance ◽  
New Phenomena ◽  
Centrifuge Rotor

The objective of this paper is to experimentally investigate the instability of an over-hung rigid centrifuge rotor partially filled with fluid. Specific emphasis has been placed on the developing process of rotor instability, the dynamical behavior of the rotor system while the instability occurs, and the frequency and direction of rotor whirl within the unstable region of rotational speeds. The effects of fluid-fill ratio on the rotor whirl frequency, the extent of the unstable region of rotational speeds, and the rotor imbalance are also studied. The detailed results clarify some issues and show some new phenomena on the instability of a rotor partially filled with fluid. The phenomena include: sub-synchronous frequency that does not result in instability of the rotor system and disappears in the unstable region at the larger fluid-fill ratios; different whirl frequencies entering the unstable region for slowly increasing and decreasing rotational speed operations; variable whirl frequency within the unstable region; hysteresis at the upper bound of the unstable region; and a break-down of the fluid free-surface.

Optical Observation of the Supercavitation Induced by High-Speed Water Entry

2000 ◽  
Vol 122 (4) ◽  
pp. 806-810 ◽  
Author(s):  
Hong-Hui Shi ◽  
Motoyuki Itoh ◽  
Takuya Takami
Keyword(s):  
Experimental Investigation ◽  
Free Surface ◽  
Shock Waves ◽  
High Speed ◽  
Bubbly Flow ◽  
Water Entry ◽  
Gas Pressure ◽  
Optical Observation ◽  
Water Tank ◽  
Experimental Facility

When a high-speed projectile penetrates into water, a cavity is formed behind the projectile. The gas enclosed in the cavity experiences a nonequilibrium process, i.e., the gas pressure decreases as the projectile moves more deeply into water. As a result, the cavity is sealed near the free surface (surface closure) and subsequently the cavity breaks up in water (deep closure). Accompanying the break-up of the cavity, secondary shock waves appear. This is the so-called supercavitation in water entry. This paper describes an experimental investigation into the water entry phenomenon. Projectiles of 342 m/s were generated from a small-bore rifle that was fixed vertically in the experimental facility. The projectiles were fired into a windowed water tank. A shadowgraph optical observation was performed to observe the entry process of the projectile and the formation and collapse of the cavity behind the projectile. A number of interesting observations relating to the motion of the free surface, the splash, the underwater bubbly flow and so on were found. [S0098-2202(00)00204-2]

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