scholarly journals Technical Note: How image processing facilitates the rising bubble technique for discharge measurement

2012 ◽  
Vol 16 (2) ◽  
pp. 345-356 ◽  
Author(s):  
K. P. Hilgersom ◽  
W. M. J. Luxemburg
Keyword(s):  
Image Processing ◽  
Water Surface ◽  
Effective Means ◽  
Technical Note ◽  
Laboratory Setup ◽  
Rising Bubble ◽  
Recent Developments ◽  
Bubble Rising ◽  
Bubble Rising Velocity ◽  
Discharge Measurements

Abstract. In this article, we rehabilitate the integrating rising bubble technique as an effective means of obtaining discharge measurements. Since Sargent (1981, 1982a), the technique has not been applied widely, mainly as a result of practical difficulties. We hypothesize that modern image processing techniques can greatly improve the rising bubble technique. We applied the technique in both a laboratory setup and a field study, after determining the bubble rising velocity for our nozzles in the specific case. During our measurements, we captured digital photographs of the bubble envelope at the water surface, each picture being a single measurement of the discharge. The photographs were corrected for lens distortion and reprojected so that accurate distances on water surface level could be obtained. This easy digital procedure resulted in accurate discharge measurements, even when turbulence was involved and the averages of multiple image analyses yielded good results. The study shows that the rising bubble technique can be a preferable discharge gauging technique in some situations. Recent developments in image processing facilitate the method substantially.

scholarly journals Technical Note: How image processing facilitates the Rising Bubble Technique for discharge measurement

2011 ◽  
Vol 8 (5) ◽  
pp. 8499-8531
Author(s):  
K. P. Hilgersom ◽  
W. M. J. Luxemburg
Keyword(s):  
Image Processing ◽  
Water Surface ◽  
Effective Means ◽  
Technical Note ◽  
Laboratory Setup ◽  
Rising Bubble ◽  
Recent Developments ◽  
Bubble Rising ◽  
Bubble Rising Velocity ◽  
Discharge Measurements

Abstract. In this article, we rehabilitate the integrating rising bubble technique as an effective means of obtaining discharge measurements. Since Sargent (1981, 1982a), the technique has not been applied widely, mainly as a result of practical difficulties. We hypothesize that modern image processing techniques can greatly improve the rising bubble technique. We applied the technique in both a laboratory setup and a field study, after calibrating the bubble rising velocity for our nozzles in the specific case. During our measurements, we captured digital photographs of the bubble envelope at the water surface, each picture being a single measurement of the discharge. The photographs were corrected for lens distortion and reprojected so that accurate distances on water surface level could be obtained. This easy digital procedure resulted in accurate discharge measurements, even when turbulence was involved and the averages of multiple image analyses yielded good results. The study shows that the rising bubble technique can be a preferable discharge gauging technique in some situations. Recent developments in image processing facilitate the method substantially.

Simulation of Rising Bubble With Conservative Level Set Method

2007 ◽  
Author(s):  
Luka Sˇtrubelj ◽  
Iztok Tiselj
Keyword(s):  
Level Set Method ◽  
Level Set ◽  
Test Case ◽  
Final Shape ◽  
Spherical Bubble ◽  
Rising Bubble ◽  
Bubble Rising ◽  
Bubble Rising Velocity ◽  
Viscous Stresses ◽  
Conservative Level Set

Conservative level set method, introduced by E. Olsson and G. Kreis in 2005 is discussed. The test case with rising bubble consists of spherical bubble of smaller density in stagnant liquid of higher density. Due to the buoyancy spherical bubble is rising up and changing its shape. After certain time the bubble reaches final velocity and final shape. An in-house code was used to perform the simulations. The final shape of the bubble was investigated and also build-up of the bubble rising velocity, starting from the rest exhibiting an overshoot before reaching its final asymptotic value. This test allows testing of numerical model which has to accurately take into account buoyancy, viscous stresses and surface tension effects.

Software pattern recognition applied to nanodiffraction patterns from a STEM instrument

1986 ◽  
Vol 44 ◽  
pp. 694-695
Author(s):  
G.Y. Fan ◽  
J.M. Cowley
Keyword(s):  
Image Processing ◽  
Pattern Recognition ◽  
Computer Software ◽  
Processing System ◽  
Light Level ◽  
Host Computer ◽  
Low Light ◽  
Image Processing System ◽  
Recent Developments ◽  
On Line

In recent developments, the ASU HB5 has been modified so that the timing, positioning, and scanning of the finely focused electron probe can be entirely controlled by a host computer. This made the asynchronized handshake possible between the HB5 STEM and the image processing system which consists of host computer (PDP 11/34), DeAnza image processor (IP 5000) which is interfaced with a low-light level TV camera, array processor (AP 400) and various peripheral devices. This greatly facilitates the pattern recognition technique initiated by Monosmith and Cowley. Software called NANHB5 is under development which, instead of employing a set of photo-diodes to detect strong spots on a TV screen, uses various software techniques including on-line fast Fourier transform (FFT) to recognize patterns of greater complexity, taking advantage of the sophistication of our image processing system and the flexibility of computer software.

SIMULATION OF AN AXISYMMETRIC RISING BUBBLE BY A MULTIPLE RELAXATION TIME LATTICE BOLTZMANN METHOD

2009 ◽  
Vol 23 (24) ◽  
pp. 4907-4932 ◽  
Author(s):  
ABBAS FAKHARI ◽  
MOHAMMAD HASSAN RAHIMIAN
Keyword(s):  
Free Surface ◽  
Lattice Boltzmann Method ◽  
Lattice Boltzmann ◽  
Rise Velocity ◽  
Rising Bubble ◽  
Wide Range ◽  
Theoretical Predictions ◽  
Multiple Relaxation Time ◽  
Bubble Rising ◽  
Boltzmann Method

In this paper, the lattice Boltzmann method is employed to simulate buoyancy-driven motion of a single bubble. First, an axisymmetric bubble motion under buoyancy force in an enclosed duct is investigated for some range of Eötvös number and a wide range of Archimedes and Morton numbers. Numerical results are compared with experimental data and theoretical predictions, and satisfactory agreement is shown. It is seen that increase of Eötvös or Archimedes number increases the rate of deformation of the bubble. At a high enough Archimedes value and low Morton numbers breakup of the bubble is observed. Then, a bubble rising and finally bursting at a free surface is simulated. It is seen that at higher Archimedes numbers the rise velocity of the bubble is greater and the center of the free interface rises further. On the other hand, at high Eötvös values the bubble deforms more and becomes more stretched in the radial direction, which in turn results in lower rise velocity and, hence, lower elevations for the center of the free surface.

Mixing of Matter by a Rising Bubble Near a Wall

2011 ◽  
Author(s):  
Toru Koso ◽  
Hiroyuki Iwashita ◽  
Fumihiko Usuki
Keyword(s):  
Large Scale ◽  
Uv Light ◽  
Fluid Motion ◽  
Turbulent Diffusion Coefficient ◽  
Air Bubble ◽  
Rising Bubble ◽  
Mass Dispersion ◽  
Mixing Patterns ◽  
Bubble Rising ◽  
Near Wall

The turbulent mixing of liquid mass caused by an air bubble rising near a wall in a still liquid in a pipe is investigated experimentally using a photochromic dye. A part of the liquid is activated by UV light and subjected to the fluid motion caused by a zigzag rising bubble of which Reynolds number is 214. The visualized mixing patterns showed that the dye is mixed by vortex motions in the bubble wake that is similar to the case of a bubble rising in the center of the pipe. The concentration distributions were deduced from the dye images using Lambert-Beer’s law and the turbulent diffusion coefficient (TDC) was evaluated from the temporal changes in the mass dispersion. The TDCs showed that a near-wall bubble generates stronger mixing than for a bubble in the center of the pipe. This stronger mixing can be attributed to the large-scale vortices observed for a near-wall bubble, which remains active for a longer time due to the lack of oppositely rotating vortices and mixes more fluids.

Effect of bed temperature on bubble size and bubble rising velocity in a semi-cylindrical slugging fluidized bed.

1990 ◽  
Vol 23 (6) ◽  
pp. 765-767 ◽  
Author(s):  
Yasuo Hatate ◽  
Kazuya Ijichi ◽  
Yoshimitsu Uemura ◽  
Mitsunobu Migita ◽  
Desmond F. King
Keyword(s):  
Fluidized Bed ◽  
Bubble Size ◽  
Bed Temperature ◽  
Bubble Rising ◽  
Bubble Rising Velocity

scholarly journals Technical Note: Quantifying music-dance synchrony with the application of a deep learning-based 2D pose estimator

2020 ◽  
Author(s):  
Filip Potempski ◽  
Andrea Sabo ◽  
Kara K Patterson
Keyword(s):  
Deep Learning ◽  
Motor Performance ◽  
Data Extraction ◽  
Effective Means ◽  
Technical Note ◽  
Novel Method ◽  
Synchronous Condition ◽  
The Mean ◽  
Repeated Training

AbstractDance interventions are more effective at improving gait and balance outcomes than other rehabilitation interventions. Repeated training may culminate in superior motor performance compared to other interventions without synchronization. This technical note will describe a novel method using a deep learning-based 2D pose estimator: OpenPose, alongside beat analysis of music to quantify movement-music synchrony during salsa dancing. This method has four components: i) camera setup and recording, ii) tempo/downbeat analysis and waveform cleanup, iii) OpenPose estimation and data extraction, and iv) synchronization analysis. Two trials were recorded: one in which the dancer danced synchronously to the music and one where they did not. The salsa dancer performed a solo basic salsa step continuously for 90 seconds to a salsa track while their movements and the music were recorded with a webcam. This data was then extracted from OpenPose and analyzed. The mean synchronization value for both feet was significantly lower in the synchronous condition than the asynchronous condition, indicating that this is an effective means to track and quantify a dancer’s movement and synchrony while performing a basic salsa step.

Investigation of single bubble rising velocity in LBE by transparent liquids similarity experiments

2018 ◽  
Vol 108 ◽  
pp. 204-213 ◽  
Author(s):  
Chaodong Zhang ◽  
Danna Zhou ◽  
Rongyuan Sa ◽  
Qingsheng Wu
Keyword(s):  
Single Bubble ◽  
Bubble Rising ◽  
Bubble Rising Velocity
Sign in / Sign up

Export Citation Format

Share Document