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.

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.

Computational Estimation of Bubble Gas Velocity for Slug Flow Pattern in Horizontal Pipes Using Image Processing Technique

2012 ◽  
Author(s):  
María T. Valecillos ◽  
Carlos H. Romero ◽  
María A. Márquez ◽  
Sissi D. Vergara
Keyword(s):  
Image Processing ◽  
Flow Pattern ◽  
Slug Flow ◽  
High Speed ◽  
Processing Technique ◽  
Image Processing Technique ◽  
Gas Velocity ◽  
Two Phase ◽  
Horizontal Pipes ◽  
Computational Estimation

Two-phase slug flow pattern is one of the most common flow patterns present in many industries, therefore its study becomes relevant. The aim of this work was to develop an automated computational program to determine the bubble gas velocity associated to gas-liquid two-phase slug flow by using video digital image processing technique. In order to obtain the images for the analysis, experiments were carried out using a pipe bench for air-water two-phase flow. The experimental facility is located in Simon Bolivar University, in Venezuela. The system has three pipes with different internal diameters and can be rotated around its axis and fixed at any inclination angle from horizontal to vertical flow. The tests were run in a horizontal pipeline of 0.03175m of internal pipe diameter and 8m long. For slug flow visualization a high speed camera Kodak Ektapro 4540mx imager was used. The camera was located in an x/D relation corresponding to 249 from the pipe inlet, ensuring the complete development of the flow. The camera allowed a maximum acquisition velocity of 4500 frames per second. The superficial velocity range was 0.16–1.79m/s and 0.16–1.26m/s for air and water, respectively. To summarize, 165 tests were performed and 1320000 images were analyzed with 20 flow rate combinations. The computational application was validated by comparing it with the velocities measured manually over selected images. Results obtained were compared to several correlations such as Bendiksen [1], Cook & Behnia [2] and Wang et al. [3].

Determination of Two-Phase Flow Void Fraction of R600a in a Horizontal Smooth Tube

2012 ◽  
Author(s):  
Özden Ağra ◽  
Hakan Demir ◽  
Ş. Özgür Atayılmaz ◽  
Ahmet Yurtseven ◽  
A. Selim Dalkılıç ◽  
...  
Keyword(s):  
Neural Network ◽  
Void Fraction ◽  
High Speed ◽  
Saturation Temperature ◽  
Horizontal Tube ◽  
Processing Technique ◽  
Image Processing Technique ◽  
Two Phase ◽  
Void Fractions

In this paper, the void fraction of alternative refrigerant R600a flowing inside horizontal tube is determined by means of an experimental technique, well known correlations in the literature and a generalized neural network analysis. The horizontal tube is made from smooth glass tubing of 4 mm inner diameter. The test runs are done at average saturated condensing temperatures between 30 and 40 °C while the average qualities and the mass fluxes are between 0.45–0.91 and 68.5–138.1 kg m-2s-1 respectively. The flow regime determination inside the tube is performed by means of sight glasses placed at the inlet and outlet sections of the test section, used for in-tube condensation tests, virtually. An image processing technique, performed by means of a high speed camera, is used to determine the void fractions of stratified and annular condensing flow of R600a experimentally. The void fractions are determined using relevant measured data together with 11 different void fraction models and correlations reported in the open literature analytically. Artificial neural network (ANN) analysis is developed to determine the void fractions numerically. For this aim, mass flow rate, average vapor quality, saturation temperature, liquid and vapor densities, liquid and vapor dynamic viscosities and surface tension are selected as the input parameters, while the void fraction is selected as the output. Three-layer network is used for predicting the void fraction. The number of the neurons in the hidden layer was determined by a trial and error process evaluating the performance of the network and standard sensitivity analysis. The measured void fraction values are found to be in good agreement with those from ANN analysis and correlations in the literature. It is also seen that the trained network are more predictive on the determination of void fraction than most of the investigated correlations.

scholarly journals Experimental and Analytical Characterization of Drop Impact Behavior for a Mobile Haptic Actuator

2017 ◽  
Author(s):  
Byungjoo Choi ◽  
Jiwoon Kwon ◽  
Yongho Jeon ◽  
Moon Gu Lee
Keyword(s):  
High Speed ◽  
Damping Ratio ◽  
Free Fall ◽  
Element Model ◽  
Impact Behavior ◽  
Air Resistance ◽  
Impact Reliability ◽  
The Impact ◽  
The Finite Element Model

Impact characterization of linear resonant actuator (LRA) is studied experimentally by newly developed drop tester, which can control various experimental uncertainty such as rotational moment, air resistance, secondary impact and so on. The feasibility of this test apparatus was verified by comparison with free fall test. By utilizing a high-speed camera and measuring the vibrational displacement of spring material, the impact behavior was captured and the damping ratio of the system was defined. Based on the above processes, the finite element model was established and the experimental and analytical results were successfully correlated. Finally, the damage of the system from impact loading can be expected by developed model and as a result, this research can improve the impact reliability of LRA.

scholarly journals The Use of High-Speed Cameras as a Tool for the Characterization of Raindrops in Splash Laboratory Studies

Water ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 2851
Author(s):  
María Fernández-Raga ◽  
Marco Cabeza-Ortega ◽  
Víctor González-Castro ◽  
Piet Peters ◽  
Meindert Commelin ◽  
...  
Keyword(s):  
High Speed ◽  
Calibration Procedure ◽  
Terminal Velocity ◽  
Second Phase ◽  
The Real ◽  
Droplet Sizes ◽  
Water Drops ◽  
Automatic Image Recognition ◽  
Two Phases

Measuring the characteristics of raindrops is essential for different processes studies. There have been many methods used throughout history to measure raindrops. In recent years, automatic image recognition and processing systems have been used with high-speed cameras to characterize rainfall by obtaining the spectrum of droplet sizes and their speeds and thus being able to use this technology to calibrate rainfall simulators. In this work, two phases were carried out: in the first one, individual drops with terminal speeds of different sizes were measured and processed both in speed and in shape with a high-speed camera; and in the second phase, a calibration procedure was designed but in multidrop images, determining the characteristics of the drops produced by a rain simulator. According to results, the real shape of each drop depending on the size was determined, from round to ovaloid shapes, and the terminal velocity of water drops with different sizes was measured. Based on the rain images used to calibrate a rainfall simulator, it was observed that, with a higher intensity of rain, the drops produced were smaller, which contrasts with real rain, in which just the opposite happens. This calibration evaluates their resemblance to reality, calculates the real kinetic energy of the rain they produce and see if they can be used to model events in nature.

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 Ultrasound-guided biopsy of breast calcifications using a new image processing technique: initial experience

2018 ◽  
Vol 51 (2) ◽  
pp. 106-108 ◽  
Author(s):  
Almir Galvão Vieira Bitencourt ◽  
Luciana Graziano ◽  
Camila Souza Guatelli ◽  
Maria Luiza Lima Albuquerque ◽  
Elvira Ferreira Marques
Keyword(s):  
Image Processing ◽  
Ultrasound Imaging ◽  
Stereotactic Biopsy ◽  
Processing Technique ◽  
Image Processing Technique ◽  
Initial Experience ◽  
Ultrasound Guided ◽  
Imaging Processing ◽  
Alternative Means

Abstract The aim of this paper is to describe the use of a new ultrasound imaging processing technique to guide biopsies of suspicious breast calcifications. We used this technique in 13 patients with suspicious breast calcifications that could not be submitted to stereotactic biopsy. Suspicious calcifications were identified by ultrasound, and the biopsy was successfully performed in all cases. Although mammography continues to be the method of choice for the detection and characterization of microcalcifications, this new technique can be an alternative means of guiding biopsy procedures in selected patients who are not candidates for stereotactic biopsy.

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