Flow analysis of two-dimensional pulsed jets by particle image velocimetry

2001 ◽  
Vol 31 (5) ◽  
pp. 519-532 ◽  
Author(s):  
J. C. Béra ◽  
M. Michard ◽  
N. Grosjean ◽  
G. Comte-Bellot
Author(s):  
Jean Brunette ◽  
Rosaire Mongrain ◽  
Rosaire Mongrain ◽  
Adrian Ranga ◽  
Adrian Ranga ◽  
...  

Myocardial infarction, also known as a heart attack, is the single leading cause of death in North America. It results from the rupture of an atherosclerotic plaque, which occurs in response to both mechanical stress and inflammatory processes. In order to validate computational models of atherosclerotic coronary arteries, a novel technique for molding realistic compliant phantom featuring injection-molded inclusions and multiple layers has been developed. This transparent phantom allows for particle image velocimetry (PIV) flow analysis and can supply experimental data to validate computational fluid dynamics algorithms and hypothesis.


Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Ahmad Falahatpisheh ◽  
Arash Kheradvar

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.


Author(s):  
Nicholas Stanley ◽  
Ashley Ciero ◽  
William Timms ◽  
Rodward L. Hewlin

Abstract In recent years, blood flow analysis of diseased arterial mock vessels using particle image velocimetry (PIV) has been hampered by the inability to fabricate optically clear anatomical vessel models that realistically replicate the complex morphology of arterial vessels and provide highly resolved flow images of flow tracer particles. The aim of the present work is to introduce an approach for producing optically clear rigid anatomical models that are suitable for PIV analysis using a common 3-D SLA inkjet printing process (using a Formlabs Form 2 3-D printer) and stock clear resin (RS-F2-GPCL-04). By matching the index of refraction (IOR) of the working fluid to the stock clear resin material, and by printing the part in a 45-degree print orientation, a clear anatomical model that allows clear visualization of flow tracer particles can be produced which yields highly resolved flow images for PIV analyses. However, a 45-degree print orientation increases the need for post processing due to an increased amount of printed support material. During post processing, the part must be wet sanded in several steps and surface finished with Novus Plastic Polish 3 Step System to achieve the final surface finish needed to yield high quality flow images. The fabrication methodology of the clear anatomical models is described in detail.


Author(s):  
Eitaro Koyabu ◽  
Tetsuhiro Tsukiji ◽  
Yoshito Matsumura ◽  
Taizo Sato

The simplified test model of the commercial reciprocating compressor for an automotive air-conditioner is used to measure the displacement of the suction valves using a strain gauge and to investigate the velocity distributions of the discharge flow from the valves using the particle image velocimetry system. This paper is focused on the effects of shape of the suction valve on the vibration-reduction. The size of the suction valve hole and the width of the tip of the suction valve are changed as main parameters of the valve shape. First, the size of the conventional valve hole and the width of the tip of the conventional valve are changed and seven new valves are manufactured to reduce the vibration of the valve. Consequently, it is found that one shape of the new valves is the most effective for the vibration-reduction. Next, the influence of the natural frequency on the vibration-reduction is investigated using one shape of the new valves by changing the material and the thickness of the valve. In addition, the relation between the conventional valve and the new valves are also estimated by the pressure loss. Finally, the reason of the vibration-reduction for one shape of the new valves is discussed from the results of the flow analysis around the valve. The vibration-reduction for one shape of the new valves is confirmed by measurement of the displacement of the valve in the reciprocating compressor for the automotive air-conditioner.


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