scholarly journals smartPIV – an app for flow visualization by cross-correlation and optical flow using smartphones

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Patrick Mäder ◽  
Jonas Hüther ◽  
Sebastian Jeschke ◽  
Constanze Poll ◽  
Henning Otto ◽  
...  
Keyword(s):  
Flow Visualization ◽  
Particle Tracking Velocimetry ◽  
Cross Correlation ◽  
Fluid Flows ◽  
Optical Methods ◽  
Basic Principles ◽  
Set Up ◽  
Particle Imaging ◽  
Visualization Techniques ◽  
Linear Nature

In recent years smartphones considerably changed our communication and are used on a daily (or even every minute) basis especially by students without any difficulties. Fluid flows also belong to our daily experiences. However, the education of the basic principles of fluid mechanics is sometimes cumbersome due to its non-linear nature. This problem may be tackled in practical sessions applying flow visualization techniques in wind or water tunnels and directly learn from own observations. Nowadays, often optical methods like particle imaging velocimetry (PIV) or particle tracking velocimetry (PTV) are used for these purposes. A typical PIV/PTV setup consists of a (double)pulse laser, a scientific camera and a synchronization device. The costs for this equipment can easily add up to more than 100,000 euros and the installations and set up of the systems requires experiences and is complex. For these reasons Universities often only offer practical courses for a small amount of students and the students may not be allowed to use and set up the systems by their own as the equipment is also needed for scientific research. Due to the COVID-19 pandemic it is also often not allowed to share equipment or even to work in larger groups during practical sessions.

Visualizing Fluid Flows With X-Rays

2007 ◽  
Author(s):  
Theodore J. Heindel ◽  
Terrence C. Jensen ◽  
Joseph N. Gray
Keyword(s):  
Computed Tomography ◽  
Flow Visualization ◽  
Three Dimensional ◽  
Fluid Flows ◽  
X Rays ◽  
Radiographic Images ◽  
Optical Access ◽  
X Ray ◽  
X Ray Computed ◽  
Density Map

There are several methods available to visualize fluid flows when one has optical access. However, when optical access is limited to near the boundaries or not available at all, alternative visualization methods are required. This paper will describe flow visualization using an X-ray system that is capable of digital X-ray radiography, digital X-ray stereography, and digital X-ray computed tomography (CT). The unique X-ray flow visualization facility will be briefly described, and then flow visualization of various systems will be shown. Radiographs provide a two-dimensional density map of a three dimensional process or object. Radiographic images of various multiphase flows will be presented. When two X-ray sources and detectors simultaneously acquire images of the same process or object from different orientations, stereographic imaging can be completed; this type of imaging will be demonstrated by trickling water through packed columns and by absorbing water in a porous medium. Finally, local time-averaged phase distributions can be determined from X-ray computed tomography (CT) imaging, and this will be shown by comparing CT images from two different gas-liquid sparged columns.

Applications of Multiple Objective Genetic Algorithms in the Optimization Design of Tracked Self-Moving Power’s Layout

2013 ◽  
Vol 307 ◽  
pp. 161-165
Author(s):  
Hai Jin ◽  
Jin Fa Xie
Keyword(s):  
Optimization Design ◽  
Pareto Front ◽  
Layout Optimization ◽  
Multiple Objective ◽  
Multi Objective Optimization ◽  
Layout Problem ◽  
Basic Principles ◽  
Multi Objective ◽  
Multi Objective Genetic Algorithm ◽  
Set Up

A multi-objective genetic algorithm is applied into the layout optimization of tracked self-moving power. The layout optimization mathematical model was set up. Then introduced the basic principles of NSGA-Ⅱ, which is a Pareto multi-objective optimization algorithm. Finally, NSGA-Ⅱwas presented to solve the layout problem. The algorithm was proved to be effective by some practical examples. The results showed that the algorithm can spread toward the whole Pareto front, and provide many reasonable solutions once for all.

scholarly journals Imaging the Subsurface: How Different Visualizations of Cross-sections Affect the Sense of Uncertainty

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Ane Bang-Kittilsen ◽  
Terje Midtbø
Keyword(s):  
Cross Sections ◽  
Open Data ◽  
Question Mark ◽  
Reference Information ◽  
Geological Information ◽  
Crucial Information ◽  
Set Up ◽  
Web Experiment ◽  
The Right ◽  
Visualization Techniques

AbstractGeologists struggle to communicate the uncertainty that arise when mapping and interpreting the geological subsurface. Today, open data sharing policies make new value of geological information possible for a broader user group of non-experts. It is crucial to develop standard methods for visualizing uncertainty to increase the usability of geological information. In this study, a web experiment was set up to analyze whether and how different design choices influence the sense of uncertainty. Also, questions about the intuitiveness of symbols were asked. Two-hundred ten participants from different countries completed the experiment, both experts and non-experts in geology. Traditional visualization techniques in geology, like dashed lines, dotted lines and question mark, were tested. In addition, other visualizations were tested, such as hatched area and variations of symbol size, zoom levels and reference information. The results show that design choices have an impact on the participants’ assessment of uncertainty. The experts inquire about crucial information if it is not present. The results also suggest that when visualizing uncertainty, all the elements in the representation, and specifically the line and area symbols that delineate and colour the features, must work together to make the right impression.

Characterization and Optimization of the Flow Pattern Inside a Diaphragm Blood Pump Based on Flow Visualization Techniques

ASAIO Journal ◽  
1998 ◽  
Vol 44 (5) ◽  
pp. M714-M718 ◽  
Author(s):  
Masako Nakata ◽  
Toru Masuzawa ◽  
Eisuke Tatsumi ◽  
Yoshiyuki Taenaka ◽  
Takashi Nishimura ◽  
...  
Keyword(s):  
Flow Visualization ◽  
Flow Pattern ◽  
Blood Pump ◽  
Visualization Techniques

Aerodynamic Characteristics of Asymmetric Bluff Bodies

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
J. C. Hu ◽  
Y. Zhou
Keyword(s):  
Bluff Body ◽  
Laser Doppler Anemometry ◽  
Vortex Formation ◽  
Aerodynamic Characteristics ◽  
Bluff Bodies ◽  
Reynolds Stresses ◽  
Freestream Velocity ◽  
Drag And Lift ◽  
Particle Imaging ◽  
Visualization Techniques

The wake of asymmetric bluff bodies was experimentally measured using particle imaging velocimetry, laser Doppler anemometry, load cell, hotwire, and flow visualization techniques at Re=2600–8500 based on the freestream velocity and the characteristic height of the bluff bodies. Asymmetry is produced by rounding some corners of a square cylinder and leaving others unrounded. It is found that, with increasing corner radius, the flow reversal region is expanded, and the vortex formation length is prolonged. Accordingly, the vortex shedding frequency increases and the base pressure rises, resulting in a reduction in the mean drag as well as the fluctuating drag and lift. It is further found that, while the asymmetric cross section of the cylinder causes the wake centerline to shift toward the sharp corner side of the bluff body, the wake remains globally symmetric about the shifted centerline. The near wake of asymmetric bluff bodies is characterized in detail, including the Reynolds stresses, characteristic velocity, and length scale, and is further compared with that of the symmetric ones.

Characterization of a Newly Designed Test Bench for Investigations of Flame-Wall-Interaction

2021 ◽  
Author(s):  
Rahand Dalshad ◽  
Tobias Sander ◽  
Michael Pfitzner
Keyword(s):  
Test Bench ◽  
Turbine Blades ◽  
Thermal Design ◽  
Optical Methods ◽  
Detailed Knowledge ◽  
Combustion Chambers ◽  
First Results ◽  
Wall Interaction ◽  
Set Up ◽  
Near Wall

Abstract For the thermal design of combustion chambers and turbine blades in jet engines, a detailed knowledge of the combustion and of the heat loads to the walls is necessary. In general, high operating temperatures and reduced combustor size are striven for in order to increase engine efficiency and reduce weight. Consequently, the components are exposed to temperatures above the melting point of the materials and there is a growing risk of incomplete combustion within the combustion chambers. To study these effects, we set up a new test bench for fundamental investigation of chemical near-wall reactions at atmospheric pressure. First results of gaseous, non-premixed near-wall CH4/air and H2/air flames are presented. Optical methods such as two-line laser-induced fluorescence thermometry and OH* chemiluminescence were applied. Further, the heat release to the wall was determined by means of inverse heat conduction calculation using the data of implemented thermocouples.

Airport Disaster Management

1985 ◽  
Vol 1 (2) ◽  
pp. 117-118
Author(s):  
G.P. Bergot
Keyword(s):  
Disaster Management ◽  
Civil Aviation ◽  
International Civil Aviation Organization ◽  
Disaster Plan ◽  
Basic Principles ◽  
Set Up ◽  
Disaster Control ◽  
And Control ◽  
Medical Policy

Coping with an airport disaster is difficult. It is enough to have once been the witness of such an event to understand the enormity of the problem. Instantaneously, the routine atmosphere becomes a nightmare. There are smoke, flames, vehicles, useful people and useless people and above all, the dead, the injured, and the uninjured survivors, some of whom are running about.An airport disaster plan should be carefully set up and applied as strictly as possible. Many features exist in our favor: (a) we know the place; (b) we can roughly evaluate in advance the magnitude of the problem as far as the number of victims is concerned, thanks to the International Civil Aviation Organization (ICAO) studies; (c) we can keep in mind the classification of the injured and the medical policy with which now all seem to agree, that is to give on-site immediate care and control evacuation; and (d) we can utilize the medical resources of the surrounding community in a co-ordinated way. This paper summarizes the basic principles for disaster control.

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