scholarly journals Characterization and Quantification of Vortex Flow in the Human Left Ventricle by Contrast Echocardiography Using Vector Particle Image Velocimetry

2008 ◽  
Vol 1 (6) ◽  
pp. 705-717 ◽  
Author(s):  
Geu-Ru Hong ◽  
Gianni Pedrizzetti ◽  
Giovanni Tonti ◽  
Peng Li ◽  
Zhao Wei ◽  
...  
Keyword(s):  
Particle Image Velocimetry ◽  
Left Ventricle ◽  
Vortex Flow ◽  
Particle Image ◽  
Contrast Echocardiography ◽  
Vector Particle ◽  
Image Velocimetry ◽  
Human Left Ventricle

Abstract 14952: Volumetric Echocardiographic Particle Image Velocimetry (V-Echo-PIV)

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Ahmad Falahatpisheh ◽  
Arash Kheradvar
Keyword(s):  
Particle Image Velocimetry ◽  
Particle Image ◽  
Contrast Echocardiography ◽  
Ultrasound Contrast Agent ◽  
Three Dimensions ◽  
Small Scale ◽  
High Temporal Resolution ◽  
Two Dimensional ◽  
Particle Image Velocimetry Technique ◽  
Image Velocimetry

Introduction: The two-dimensional (2D) echocardiographic particle image velocimetry technique that was introduced in 2010 received much attention in clinical cardiology. Cardiac flow visualization based on contrast echocardiography results in images with high temporal resolution that are obtainable at relatively low cost. This makes it an ideal diagnostic and follow-up tool for routine clinical use. However, cardiac flow in a cardiac cycle is multidirectional with a tendency to spin in three dimensions rather than two-dimensional curl. Here, for the first time, we introduce a volumetric echocardiographic particle image velocimetry technique that robustly acquires the flow in three spatial dimensions and in time: Volumetric Echocardiographic Particle Image Velocimetry (V-Echo-PIV). Methods: V-Echo-PIV technique utilizes matrix array 3D ultrasound probes to capture the flow seeded with an ultrasound contrast agent (Definity). For this feasibility study, we used a pulse duplicator with a silicone ventricular sac along with bioprosthetic heart valves at the inlet and outlet. GE Vivid E9 system with an Active Matrix 4D Volume Phased Array probe at 30 Hz was used to capture the flow data (Figure 1). Results: The 3D particle field was obtained with excellent spatial resolution without significant noise (Figure 1). 3D velocity field was successfully captured for multiple cardiac cycles. Flow features are shown in Figure 2 where the velocity vectors in two selected slices and some streamlines in 3D space are depicted. Conclusions: We report successful completion of the feasibility studies for volumetric echocardiographic PIV in an LV phantom. The small-scale features of flow in the LV phantom were revealed by this technique. Validation and human studies are currently in progress.

Vortex flow and lift generation of a non-slender reverse delta wing

2016 ◽  
Vol 231 (13) ◽  
pp. 2438-2451
Author(s):  
T Lee ◽  
LS Ko
Keyword(s):  
Particle Image Velocimetry ◽  
Lift Force ◽  
Vortex Flow ◽  
Particle Image ◽  
Delta Wing ◽  
Lower Surface ◽  
Force Balance ◽  
Flow Parameters ◽  
Image Velocimetry ◽  
Spanwise Vortex

The vortex flow and lift force generated by a 50°-sweep non-slender reverse delta wing were investigated via particle image velocimetry, together with flow visualization and force balance measurement, at Re = 11,000. The non-slender reverse delta wing produced a delayed stall but a lower lift compared to its delta wing counterpart. The stalling mechanism was also found to be triggered by the disruption of the multiple spanwise vortex filaments developed over the upper wing surface. The vortex flowfield was, however, characterized by the co-existence of reverse delta wing vortices and multiple shear-layer vortices. The outboard location of the reverse delta wing vortex further implies that the lift force is mainly generated by the wing lower surface while the upper surface acts as a wake generator. The spatial progression of the flow parameters of the vortex generated by the non-slender reverse delta wing as a function of α was also discussed.

Abstract 13873: Quantitative Characteristics of Left Ventricular Vortex Flow in the Short and Long Axis Views by High Frame Rate Echocardiographic Particle Image Velocimetry

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Haruhiko Abe ◽  
Kasumi Masuda ◽  
Toshihiko Asanuma ◽  
Hikaru Koriyama ◽  
Yukihiro Koretsune ◽  
...  
Keyword(s):  
Particle Image Velocimetry ◽  
Vortex Flow ◽  
Cardiac Cycle ◽  
Particle Image ◽  
Left Ventricular ◽  
Frame Rate ◽  
Vortex Strength ◽  
High Frame Rate ◽  
Image Velocimetry ◽  
Quantitative Characteristics

Background: Vortex flow in the left ventricle (LV) has three-dimensional structure and plays an important role in avoiding excessive dissipation of energy. However, quantitative characteristics of long and short axis (LAX and SAX) vortex flow have not been elucidated. Echocardiographic particle image velocimetry (Echo-PIV) is an emerging technique to evaluate instantaneous vortical flow inside the LV. However, it has a limitation of underestimation of high velocities due to limited frame rate. Moreover, previous investigations have mainly focused on vortex from LAX view. Therefore, we used high frame rate Echo-PIV to quantitate vortex flow in SAX as well as in LAX views to understand characteristics of vortex three-dimensionally. Methods: Echocardiographic contrast images of the LV SAX and LAX were acquired from 8 open-chest healthy dogs. The acquisition frame rate was 135 frames per second and the contrast bubbles density was optimized for blood flow analysis. Echo-PIV analysis was performed off-line by using commercially available software and vorticity data were calculated in the region of interest (ROI) throughout the cardiac cycle. ROI was manually placed on the vortex. Vortex strength was defined as the averaged vorticity within the ROI. Results: In SAX, counterclockwise vortex was seen near the anterior wall, and in LAX clockwise vortex was seen in the anterior mid-ventricle. Both in SAX and LAX views, vortex strength showed significant phasic variations being largest in isovolumic contraction (vortex strength, SAX 9.2±2.3/s, p<0.001; LAX -12.0±2.4/s, p<0.001), and smallest in isovolumic relaxation (SAX -0.8±0.8/s, p<0.001; LAX -1.9±1.9/s, p<0.001). Conclusion: High frame rate Echo-PIV successfully demonstrated a complicated pattern of intracardiac vortex with phasic variation of its strength throughout a cardiac cycle in both SAX and LAX. This method may be a useful tool to assess physiological role of vortex in the flow dynamics.

Particle Image Velocimetry Dynamic Analysis on the Penstock Vortex Flow for the Dam Reliability Study

2021 ◽  
pp. 493-501
Author(s):  
N. M. Zahari ◽  
M. H. Zawawi ◽  
Fei Chong Ng ◽  
L. M. Sidek ◽  
Aizat Abas ◽  
...  
Keyword(s):  
Particle Image Velocimetry ◽  
Dynamic Analysis ◽  
Vortex Flow ◽  
Particle Image ◽  
Reliability Study ◽  
Image Velocimetry

Particle image velocimetry and laser Doppler anemometry experimental studies of a compressible short take-off and vertical landing ground vortex flow

2002 ◽  
Vol 216 (4) ◽  
pp. 171-187 ◽  
Author(s):  
N J Lawson ◽  
J M Eyles ◽  
K Knowles
Keyword(s):  
Particle Image Velocimetry ◽  
Vortex Flow ◽  
Particle Image ◽  
Laser Doppler Anemometry ◽  
Cross Flow ◽  
Laser Doppler ◽  
Data Set ◽  
Image Velocimetry ◽  
Vertical Landing ◽  
Dominant Frequencies

A particle image velocimetry (PIV) and laser Doppler anemometry (LDA) study of a scaled short take-off and vertical landing (STOVL) ground vortex flow is presented. The scaled flow features a compressible impinging jet in cross-flow with a moving ground plane. Mean and transient PIV and LDA velocity data are recorded from the ground vortex about the jet centre-line over a range of nozzle pressure ratios (NPR s) from 2.3 to 3.7, nozzle height—diameter ratios ( h/dn) from 3 to 10 (where dn = 12.7 mm) and cross-flow velocities (V∞) from 10 to 20 m/s, corresponding to effective velocity ratios of 19 < Ve−1 < 38. For each condition, 72 PIV vector maps were taken from the ground vortex region to generate an instantaneous and time-average data set. From the instantaneous data, a cinematic sequence was used to track the ground vortex position, which was found to fluctuate longitudinally by a root mean square distance of up to 4.47 dn and vertically by up to 2.18 dn. From the time-averaged PIV measurements, selected LDA pointwise data were taken at the average ground vortex core. Subsequent spectral analysis of the PIV time series showed the ground vortex position to fluctuate at dominant frequencies of between 2.5 and 5 Hz while the LDA data showed the velocity to fluctuate by dominant frequencies ranging between 1 and 30 Hz.

Sign in / Sign up

Export Citation Format

Share Document