Review of application of particle image velocimetry (PIV) in assessing hydraulic intake vortex formation characteristics

2020 ◽  
Author(s):  
Nurhanani A. Aziz ◽  
N. M. Zahari ◽  
Mohd Hafiz Zawawi ◽  
Aqil Azman ◽  
F. Nurhikmah ◽  
...  
Keyword(s):  
Particle Image Velocimetry ◽  
Particle Image ◽  
Vortex Formation ◽  
Image Velocimetry ◽  
Hydraulic Intake

Flow Structures in a U-Shaped Fuel Cell Flow Channel: Quantitative Visualization Using Particle Image Velocimetry

2004 ◽  
Vol 2 (1) ◽  
pp. 70-80 ◽  
Author(s):  
J. Martin ◽  
P. Oshkai ◽  
N. Djilali
Keyword(s):  
Particle Image Velocimetry ◽  
Fuel Cell ◽  
Cross Sections ◽  
Particle Image ◽  
Fluid Dynamic ◽  
Vortex Formation ◽  
Image Velocimetry ◽  
Quantitative Visualization ◽  
Image Density ◽  
Transport Channels

Flow through an experimental model of a U-shaped fuel cell channel is used to investigate the fluid dynamic phenomena that occur within serpentine reactant transport channels of fuel cells. Achieving effective mixing within these channels can significantly improve the performance of the fuel cell and proper understanding and characterization of the underlying fluid dynamics is required. Classes of vortex formation within a U-shaped channel of square cross section are characterized using high-image-density particle image velocimetry. A range of Reynolds numbers, 109⩽Re⩽872, corresponding to flow rates encountered in a fuel cell operating at low to medium current densities is investigated. The flow fields corresponding to two perpendicular cross sections of the channel are characterized in terms of the instantaneous and time-averaged representations of the velocity, streamline topology, and vorticity contours. The critical Reynolds number necessary for the onset of instability is determined, and the two perpendicular flow planes are compared in terms of absolute and averaged velocity values as well as Reynolds stress correlations. Generally, the flow undergoes a transition to a different regime when two recirculation zones, which originally develop in the U-bend region, merge into one separation region. This transition corresponds to generation of additional vortices in the secondary flow plane.

scholarly journals Evaluation of patients with a HeartMate 3 left ventricular assist device using echocardiographic particle image velocimetry

2020 ◽  
Author(s):  
Arend F. L. Schinkel ◽  
Sakir Akin ◽  
Mihai Strachinaru ◽  
Rahatullah Muslem ◽  
Dan Bowen ◽  
...  
Keyword(s):  
Blood Flow ◽  
Particle Image Velocimetry ◽  
Particle Image ◽  
Vortex Formation ◽  
Left Ventricular ◽  
Flow Dynamics ◽  
Lv Function ◽  
Image Velocimetry ◽  
Intraventricular Flow ◽  
Blood Flow Dynamics

Abstract Purpose Poor left ventricular (LV) function may affect the physiological intraventricular blood flow and physiological vortex formation. The aim of this study was to investigate the pattern of intraventricular blood flow dynamics in patients with LV assist devices (LVADs) using echocardiographic particle image velocimetry. Materials and methods This prospective study included 17 patients (mean age 57 ± 11 years, 82% male) who had received an LVAD (HeartMate 3, Abbott Laboratories, Chicago, Illinois, USA) because of end-stage heart failure and poor LV function. Eleven (64%) patients had ischemic cardiomyopathy, and six patients (36%) had nonischemic cardiomyopathy. All patients underwent echocardiography, including intravenous administration of an ultrasound-enhancing agent (SonoVue, Bracco, Milan, Italy). Echocardiographic particle image velocimetry was used to quantify LV blood flow dynamics, including vortex formation (Hyperflow software, Tomtec imaging systems Gmbh, Unterschleissheim, Germany). Results Contrast-enhanced ultrasound was well tolerated in all patients and was performed without adverse reactions or side effects. The LVAD function parameters did not change during or after the ultrasound examination. The LVAD flow was on average 4.3 ± 0.3 L/min, and the speed was 5247 ± 109 rotations/min. The quantification of LV intraventricular flow demonstrated substantial impairment of vortex parameters. The energy dissipation, vorticity, and kinetic energy fluctuation indices were severely impaired. Conclusions Echo particle velocimetry is safe and feasible for the quantitative assessment of intraventricular flow in patients with an LVAD. The intraventricular LV flow and vortex parameters are severely impaired in these patients.

scholarly journals Finite Volume Method Numerical Modelling of the Penstock Flows in Dam Intake Sector Subjected to Varying Operating Conditions with Particle Image Velocimetry Validation

2021 ◽  
Vol 86 (1) ◽  
pp. 176-186
Author(s):  
Nazirul Mubin Zahari ◽  
Mohd Hafiz Zawawi ◽  
Fei Chong Ng ◽  
Mohamad Aizat Abas ◽  
Farah Nurhikmah ◽  
...  
Keyword(s):  
Particle Image Velocimetry ◽  
Numerical Model ◽  
Particle Image ◽  
Vortex Formation ◽  
Operating Conditions ◽  
Flow Structures ◽  
Hydroelectric Power ◽  
Numerical Work ◽  
Image Velocimetry ◽  
Volume Method

The formation of vortex and swirling in any flow structures of the hydropower dam is undesirable, as it reduced the performance of turbine as well as lowered the efficiency of hydroelectric power generation. Furthermore, it could lead to the hydraulic losses at the entrance of power intakes, the blockage at the trash racks due to entrain debris and the reduction of the working life of turbines. This paper studied penstocks flows in the dam intake section numerically. The dynamics of penstocks flows at different operating conditions were analyzed to determine the vortex formation. To access the veracity of the current proposed numerical model, a validating study based on the particle image velocimetry (PIV) experiment was conducted. It was found the discrepancy between both numerical and experimental flow velocities is 12%, implying the numerical model is well-validated and the corresponding findings are acceptable. It was found that the vortex was formed in the penstock that located at the lowest level relative to other penstocks. Furthermore, the highest pressure of 4 MPa was recorded at the bottom section of the penstock which observed vortex. This numerical work provided useful insights for the future dam reliability analysis, particularly involving penstocks and intake section.

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