Wave-in-Deck Impact Loads in Relation With Wave Kinematics

2017 ◽  
Author(s):  
Jule Scharnke ◽  
Rene Lindeboom ◽  
Bulent Duz
Keyword(s):  
Particle Image Velocimetry ◽  
Particle Image ◽  
Impact Load ◽  
Breaking Waves ◽  
Offshore Structures ◽  
Small Scale ◽  
Impact Loads ◽  
Piv Measurements ◽  
Wave Kinematics ◽  
Image Velocimetry

Breaking waves have been studied for many decades and are still of interest as these waves contribute significantly to the dynamics and loading of offshore structures. In current MARIN research this awareness has led to the setup of an experiment to determine the kinematics of breaking waves using Particle Image Velocimetry (PIV). The purpose of the measurement campaign is to determine the evolution of the kinematics of breaking focussed waves. In addition to the PIV measurements in waves, small scale wave-in-deck impact load measurements on a fixed deck box were carried out in the same wave conditions. To investigate the link between wave kinematics and wave-in-deck impact loads, simplified loading models for estimating horizontal deck impact loads were applied and compared to the measured impact loads. In this paper, the comparison of the model test data to estimated loads is presented.

Time-Resolved Particle Image Velocimetry (PIV) Measurements in a Radial Diffuser Pump

2009 ◽  
Author(s):  
Jianjun Feng ◽  
Friedrich-Karl Benra ◽  
Hans Josef Dohmen
Keyword(s):  
Particle Image Velocimetry ◽  
Particle Image ◽  
Time Resolved ◽  
Piv Measurements ◽  
Part Load ◽  
Channel Characteristic ◽  
Image Velocimetry ◽  
Pump Stage ◽  
Low Specific Speed ◽  
Load Conditions

The truly time-variant unsteady flow in a low specific speed radial diffuser pump stage has been investigated by time-resolved Particle Image Velocimetry (PIV) measurements. The measurements are conducted at the midspan of the blades for the design condition and also for some severe part-load conditions. The instantaneous flow fields among different impeller channels are analyzed and compared in detail, and more attention has been paid to flow separations at part-load conditions. The analysis of the measured results shows that the flow separations at two adjacent impeller channels are quite different at some part-load conditions. The separations generally exhibit a two-channel characteristic.

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.

scholarly journals Experiments on wave propagation in grease ice: combined wave gauges and particle image velocimetry measurements

2019 ◽  
Vol 864 ◽  
pp. 876-898 ◽  
Author(s):  
Jean Rabault ◽  
Graig Sutherland ◽  
Atle Jensen ◽  
Kai H. Christensen ◽  
Aleksey Marchenko
Keyword(s):  
Wave Propagation ◽  
Particle Image Velocimetry ◽  
Particle Image ◽  
Wave Attenuation ◽  
Laboratory Data ◽  
Decomposition Analysis ◽  
Small Scale ◽  
Wave Tank ◽  
Wave Elevation ◽  
Image Velocimetry

Water wave attenuation by grease ice is a key mechanism for the polar regions, as waves in ice influence many phenomena such as ice drift, ice breaking and ice formation. However, the models presented so far in the literature are limited in a number of regards, and more insights are required from either laboratory experiments or fieldwork for these models to be validated and improved. Unfortunately, performing detailed measurements of wave propagation in grease ice, either in the field or in the laboratory, is challenging. As a consequence, laboratory data are relatively scarce, and often consist of only a couple of wave elevation measurements along the length of the wave tank. We present combined measurements of wave elevation using an array of ultrasonic probes, and water kinematics using particle image velocimetry (PIV), in a small-scale wave tank experiment. Experiments are performed over a wider frequency range than has been previously investigated. The wave elevation measurements are used to compute the wavenumber and exponential damping coefficient. In contrast to a previous study in grease ice, we find that the wavenumber is consistent with the mass loading model, i.e. it increases compared with the open water case. Wave attenuation is compared with a series of one-layer models, and we show that they satisfactorily describe the viscous damping occurring. PIV data are also consistent with exponential wave amplitude attenuation, and a proper orthogonal decomposition analysis reveals the existence of mean flows under the ice that are a consequence of the displacement and packing of the ice induced by the gradient in the wave-induced stress. Finally, we show that the dynamics of grease ice can generate eddy structures that inject eddy viscosity into the water under the grease ice, which would lead to enhanced mixing and participating in energy dissipation.

Application of Particle Image Velocimetry to a Small-Scale de Laval Nozzle

AIAA Journal ◽  
1999 ◽  
Vol 37 (7) ◽  
pp. 798-804 ◽  
Author(s):  
N. J. Lawson ◽  
G. J. Page ◽  
N. A. Halliwell ◽  
J. M. Coupland
Keyword(s):  
Particle Image Velocimetry ◽  
Laval Nozzle ◽  
Particle Image ◽  
Small Scale ◽  
Image Velocimetry ◽  
De Laval Nozzle

Simultaneous particle image velocimetry and infrared imagery of microscale breaking waves

2001 ◽  
Vol 13 (7) ◽  
pp. 1891-1903 ◽  
Author(s):  
M. H. Kamran Siddiqui ◽  
Mark R. Loewen ◽  
Christine Richardson ◽  
William E. Asher ◽  
Andrew T. Jessup
Keyword(s):  
Particle Image Velocimetry ◽  
Particle Image ◽  
Breaking Waves ◽  
Infrared Imagery ◽  
Image Velocimetry

scholarly journals Tomographic particle image velocimetry of a water-jet for low volume harvesting of fat tissue for regenerative medicine

2015 ◽  
Vol 1 (1) ◽  
pp. 345-348 ◽  
Author(s):  
Christoph Drobek ◽  
Robert Mau ◽  
Hermann Seitz
Keyword(s):  
Particle Image Velocimetry ◽  
Regenerative Medicine ◽  
Particle Image ◽  
Force Sensor ◽  
Water Jet ◽  
Fat Tissue ◽  
Cfd Simulations ◽  
Piv Measurements ◽  
Image Velocimetry ◽  
Acting Force

AbstractParticle Image Velocimetry (PIV) measurements of a water-jet for water-assisted liposuction (WAL) are carried out to investigate the distribution of velocity and therefore momentum and acting force on the human sub-cutaneous fat tissue. These results shall validate CFD simulations and force sensor measurements of the water-jet and support the development of a new WAL device that is able to harvest low volumes of fat tissue for regenerative medicine even gentler than regular WAL devices.

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