scholarly journals On Dam-Break Flow Routing in Confluent Channels

2019 ◽  
Vol 16 (22) ◽  
pp. 4384
Author(s):  
Sihan Chen ◽  
Yingjin Li ◽  
Zhong Tian ◽  
Qiang Fan
Keyword(s):  
Flow Field ◽  
Arrival Time ◽  
Processing Technique ◽  
Surface Flow ◽  
Dam Break ◽  
Image Processing Technique ◽  
Physical Experiments ◽  
Dam Break Flow ◽  
The Impact ◽  
Motion Images

The flood propagation at a confluence of channels exhibits a unique routing pattern, while there are few studies on the routing of dam-break flow in confluent channels. In this study, we conducted physical experiments and a numerical simulation to investigate the influence of different confluence angles on the routing of a dam-break flood. Experiments were carried out in smooth, transparent, rectangular prismatic channels to study the dam-break flow under four different confluence angles. The flow velocity was measured using an image processing technique, and the surface flow field was effectively captured by synchronously recording the particle motion images. Based on the variation of the water level and flow discharge, as the confluence angle increased, the retardation and abatement effects on the flood increased. Specifically, the flood arrival time was delayed by approximately 0.91% to 21.18%, and the peak flood discharge was reduced by approximately 9.05% to 58.36%. Combined with the surface flow field at the confluence and in the downstream sections, as the confluence angle increased, the impact points at the confluence and in the downstream straight sections moved upward, and the impact range was reduced. Combined with the pressure variation pattern, the routing of dam-break flow in the confluent channels experienced a process of impact-reflection-return-attenuation.

scholarly journals Robotic Model for Unmanned Crack and Corrosion Inspection

2019 ◽  
Vol 9 (1) ◽  
pp. 862-867 ◽  
Keyword(s):  
Structural Integrity ◽  
Oil And Gas ◽  
Processing Technique ◽  
High Rate ◽  
Image Processing Technique ◽  
Destructive Testing ◽  
Periodic Inspection ◽  
The Cost ◽  
The Impact ◽  
Non Destructive

After prolonged usage of materials, the formation of cracks and corrosion initiates due to stress, loading condition, the environment of operation, etc. and this affects the structural integrity of structures. Periodic inspection of structures is usually planned, especially in industries where the impact of failure could be devastating, such as oil and gas pipelines, storage tanks, vessels, and airplanes, etc. which are just a few amongst others. This inspection is often aimed at detecting cracks and corrosion of internal and external components using several forms of non-destructive testing mechanism usually performed by a specialist at a high rate. To reduce the cost of inspection as well as downtime due to inspections and maintenance, deployments of mobile robots with fault tracking and identification purpose are steadily increasing. This paper, therefore, details the implementation of an image processing technique using MATLAB to identify defects of structural elements.

scholarly journals Investigation of Flow Field inside a Savonius Rotor by Image Processing Technique with Conditional Sampling.

1993 ◽  
Vol 59 (567) ◽  
pp. 3519-3523
Author(s):  
Nobuyuki Fujisawa ◽  
Yoshikazu Taguchi ◽  
Tsuyoshi Satoh ◽  
Tomomasa Uemura ◽  
Kosuke Nagaya ◽  
...  
Keyword(s):  
Image Processing ◽  
Flow Field ◽  
Processing Technique ◽  
Image Processing Technique ◽  
Conditional Sampling ◽  
Savonius Rotor

scholarly journals Kinematic and dynamic analysis of dam break flow impact on vertical walls using weakly compressible SPH

2021 ◽  
Vol 15 (2) ◽  
Author(s):  
Petr Jančík ◽  
Tomáš Hyhlík
Keyword(s):  
Dynamic Analysis ◽  
Evaluation Method ◽  
Numerical Solutions ◽  
Vertical Wall ◽  
Dam Break ◽  
Column Height ◽  
Width Ratio ◽  
Total Force ◽  
Dam Break Flow ◽  
The Impact

This article presents the kinematic and dynamic analysis of a dam break flow based on data obtained from numerical solutions by the smoothed particle hydrodynamics (SPH) method. The method and original algorithms necessary for correct pressure evaluation are thoroughly described. The pressure evaluation method consists of data reading using virtual sensors and filtration in the time domain using the weight function. A simple convergence study showing the independency of the evaluated parameters of spatial resolution is presented together with validation of the introduced methods and algorithms using a simple hydrostatic problem and experimental data available in the literature. We focus on two parameters that describe the problem: distance of the downstream vertical wall from the edge of the liquid column and the column’s height to width ratio. We found that the impact can be divided into three consecutive phases characterized by specific kinematic (flow patterns) and dynamic (exerted pressure and forces) behavior and different roles of the investigated parameters during these phases. During the early stages of an impact, the column’s distance from the vertical wall plays a major role. A dependency between the column distance and the force peak in this stage was identified in the form of a power function. In the second stage, when a rolling wave emerges, the vertical wall position influences the shape of the wave and the pressure distribution on the wall. The total force is greater in this phase for lower column height to width ratios due to the higher total momentum of the liquid. In the third stage, when the rolling wave impacts the liquid surface, the employed methodology with two-dimensional solution and free-surface approach seems to reach its limits of applicability. A more complex modelling would be necessary to capture this phase of the impact properly.

Experimental and Numerical Characterization of Drop Impact on a Hydrophobic Cylinder

2019 ◽  
Vol 141 (8) ◽  
Author(s):  
Javid Zohrabi Chakaneh ◽  
Seyed Javad Pishbin ◽  
Alireza Sheikhi Lotfabadi ◽  
Mohammad Passandideh-Fard
Keyword(s):  
High Speed ◽  
Processing Technique ◽  
Image Processing Technique ◽  
Time Step ◽  
Cylinder Diameter ◽  
Numerical Characterization ◽  
Drop Generator ◽  
Water Drops ◽  
The Impact

In this paper, the impact of distilled water drops on hydrophobic cylinders is characterized using both experiments and numerical simulations. Water drops of 2.54 mm in diameter impact with a velocity of 1 m/s on hydrophobic cylinders. The corresponding Reynolds and Weber numbers are 2800 and 34, respectively. Three different stainless steel cylinders with diameters of 0.48 mm, 0.88 mm, and 1.62 mm were used. The surfaces of the cylinders were made hydrophobic using a special coating spray. An experimental setup consisting of a drop generator, a high-speed camera, a lighting system, and a photoelectric sensor was used to capture images of the impact with a time-step of 1 ms. The images were then analyzed using an image processing technique implemented in the matlab software. Both the centric and off-centric impacts were studied for each cylinder diameter. A numerical simulation of the impact was also obtained using an open-source code called OpenFOAM by employing its InterFoam solver. The numerical scheme used by the solver is the volume-of-fluid (VOF) method. The predicted images of the simulations were compared well with those of the captured photographs both qualitatively and quantitatively for the entire experiments. The behavior of the drop after the impact and the subsequent deformation on hydrophobic cylinders including flow instabilities, liquid breakup, and secondary drops formation were observed from both simulations and experiments. By decreasing the cylinder diameter, the breakup occurs sooner, and a smaller number of secondary drops are formed.

An image processing technique for measuring free surface of dam-break flows

2010 ◽  
Vol 50 (3) ◽  
pp. 665-675 ◽  
Author(s):  
Francesca Aureli ◽  
Andrea Maranzoni ◽  
Paolo Mignosa ◽  
Chiara Ziveri
Keyword(s):  
Image Processing ◽  
Free Surface ◽  
Processing Technique ◽  
Dam Break ◽  
Image Processing Technique

Development of 3D Impact Self-Sensing Composites Using Fracto-Mechanoluminescent EuD4TEA

2017 ◽  
Author(s):  
Brandon Holguin ◽  
James Allison ◽  
Donghyeon Ryu ◽  
Zachary Alvarez ◽  
Francisco Hernandez ◽  
...  
Keyword(s):  
High Speed ◽  
Light Emission ◽  
Impact Damage ◽  
Compressive Loading ◽  
Three Dimensional ◽  
Processing Technique ◽  
Image Processing Technique ◽  
Mechanical Stimuli ◽  
Structural Composites ◽  
The Impact

The objective of this study is to develop three dimensional (3D) impact self-sensing composites capable of localizing impact damage in through-the-thickness direction. The 3D impact self-sensing composites (3D-ISSC) are designed by embedding fracto-mechanoluminescent (FML) crystals in cells of honeycomb-cored fiber reinforced polymer (FRP) structural composites. FML crystals were shown to emit light resulting from cleavage of crystalline structures due to external mechanical stimuli. Unlike other conventional sensor networks, without supplying external electrical source, the 3D-ISSC is envisioned to monitor impact occurrences and detect damage. Instead, the emitted light will be utilized for informing severity of impact occurrences and 3D locations of the impact damage. First, FML europium-doped dibenzoylmethide triethylammonium (EuD4TEA) crystals are synthesized. Second, the synthesized EuD4TEA crystals are embedded in the honey-cored FRP structural composites to fabricate 3D-ISSC. Third, to validate its 3D self-sensing capability, Kolsky bar is employed to apply high strain-rate compressive loading to simulate impact occurrences while taking high-speed video footage for quantifying intensity of FML light emission through image processing technique.

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