Collection: research
(1 - 20 of 136)

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Kim, S. (author), Kim, D.E. (author), Euh, D.J. (author)
Thermal stratification is encountered in large pool of water increasingly being used as heat sink in new generation of advanced reactors. These large pools at near atmospheric pressure provide a heat sink for heat removal from the reactor or steam generator, and the containment by natural circulation as well as a source of water for core cooling...
conference paper 2013
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Fiscaletti, D. (author), Elsinga, G.E. (author), Westerweel, J. (author)
The present work involves the investigation of the fine scale motions in the turbulent region of a high Reynolds number air jet. In the fully developed region of the jets, the small scales of turbulence are assumed to be isotropic, and expected to contain elongated vortices (worms), whose diameter scales with the Kolmogorov length scale. Aimed...
conference paper 2013
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Ferrari, S. (author), Badas, M.G. (author), Besalduch, L.A. (author), Querzoli, G. (author)
We present a novel algorithm, namely Feature Tracking Velocimetry (FTV), which is less sensitive to the appearance and disappearance of particles and to high velocity gradients than classical Particle Image Velocimetry (PIV). The basic idea of FTV is to compare windows only where the motion detection may be successful, that is where there are...
conference paper 2013
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Lee, C.H. (author), Kim, D.Y. (author), Kim, H.D. (author), Kim, K.C. (author)
Dynamic behaviour and heat transfer characteristics of impinging droplets on a hot surface were studied experimentally. De-ionized water droplet was made through a 31G injection needle and the droplet size was 2 mm. A sapphire plate was heated up to 300ºC by a hotplate. A high speed camera was used for visualization, and the frame rate was 4000...
conference paper 2013
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Blois, G. (author), Barros, J.M. (author), Christensen, K.T. (author)
Here we report on the dynamics of immiscible fluid displacement in porous media at the microscale captured with microscopic particle image velocimetry (?PIV). The experimental challenges associated with simultaneously imaging two immiscible fluids, tracking their interface and quantifying the flow processes induced by the fluid-fluid interaction...
conference paper 2013
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Scharfman, B.E. (author), Hart, D.P. (author), Techet, A.H. (author)
The atomization of an unsteady turbulent sheet of water in air is analyzed using a combination of light field imaging (LFI) and synthetic aperture (SA) refocusing techniques. This sheet collides with and initially flows along a solid inclined plate, and imaging is performed in the region where breakup and separation from the plate begin....
conference paper 2013
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Kato, H. (author), Koike, S. (author), Nakakita, K. (author), Ito, T. (author), Shiohara, T. (author), Kato, C. (author), Iida, A. (author), Doi, Y. (author), Kato, Y. (author), Miura, Y. (author)
conference paper 2013
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Lynch, K. (author), Scarano, F. (author)
A tomographic PIV system is introduced for the instantaneous measurement of the material derivative of velocity (VMD). The system is able to operate with very short temporal separation and is therefore suitable for applications in high-speed flows. The method of operation consists of the imaging of a measurement volume using an array of 12 CCD...
conference paper 2013
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Birvalski, M. (author), Tummers, M. (author), Delfos, R. (author), Henkes, R.A.W.M. (author)
The technique for obtaining detailed velocity fields in a wavy liquid layer in stratified air/water pipe flow is described in this paper. By combining Particle Image Velocimetry (PIV) with an interface detection technique, the velocity field is resolved in the whole liquid layer. Furthermore, since the shape of the interface is resolved at each...
conference paper 2013
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Im, S. (author), Heo, G.E. (author), Sung, H.J. (author), Kim, S.K. (author)
Flow inside a scaled model of nasal cavity was measured by tomographic PIV. The model was constructed with transparent silicon. A refractive index of working fluid was matched to the model index by mixing glycerol and water. Four cameras and double pulse laser system were used for tomographic PIV. To obtain high SNR, red fluorescence particles...
conference paper 2013
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Hess, D. (author), Sastuba, M. (author), Kitzhofer, J. (author), Brücker, C. (author)
This work describes the flow around a sphere with a longitudinal hole inside. Such ring-type particles are useful in many applications like chemical reactors as catalysts (seed particles) to increase the reacting surface in the multi-phase flow. Both heat transfer and the flow structure in and around those catalysts are of interest for fixed bed...
conference paper 2013
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Sancho, I. (author), Varela, S. (author), Pallares, S. (author), Vernet, A. (author)
An axisymmetric confined, reactive and laminar flow has been analysed, both experimentally and numerically. The cavity is cylindrical with a rotating end wall varying its aspect ratio and the angular velocity of the rotating wall. The experimental techniques applied are the Particle Image Velocimetry (PIV) and the Planar Laser Induced...
conference paper 2013
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Jeon, Y.J. (author), Chatellier, L. (author), David, L. (author)
A new time-resolved PIV (TR-PIV) method is introduced by integrating both two concepts, the fluid parcel tracking [1] and the ensemble averaged correlation [2, 3]. The dynamic range is extended by applying the polynomial trajectory as the fluid motion [1]. The tracking procedure is not performed by using individual locations of the fluid parcel...
conference paper 2013
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Ono, Y. (author), Motosuke, M. (author), Honami, S. (author)
A synthetic jet is one of flow control devices that can topologically disturb surrounding flow field by adding periodic injection and suction of surrounding fluid using an oscillating membrane through an orifice. This device can be applied to the downsized fluid machinery without a net mass injection of fluid for the simplified structure. In...
conference paper 2013
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Ding, L. (author), Discetti, S. (author), Adrian, R.J. (author), Gogineni, S. (author)
Many conventional experimental methods in fluid mechanics, such as LDV and HWA, are not able to measure simultaneous acceleration fields directly. Double-pulse PIV is extended to the multiple-pulse PIV enabling people to directly extract acceleration fields as well as to achieve better accuracy in the velocity measurement [13]. We evaluate the...
conference paper 2013
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Lemke, M. (author), Sesterhenn, J. (author)
The aim of the study is the application and validation of an adjoint based data assimilation method for the determination of timedependent pressure fields from velocity data obtained by particle image velocimetry (PIV). The method is based on the full compressible Navier-Stokes equations. No additional constraints like incompressibility or...
conference paper 2013
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Alekseenko, M.V. (author), Bilsky, A.V. (author), Dulin, V.M. (author), Markovich, D.M. (author), Tokarev, M.P. (author)
The present work is devoted to the application of the Tomographic PIV technique to study coherent structures in a swirling turbulent jet. The aim of the paper is to study the possibilities of caring out tomographic PIV measurements with the large depth of a volume configuration in the swirling jet setup. It is recognized that an extension of the...
conference paper 2013
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Roosenboom, E.W.M. (author), Geisler, R. (author), Agocs, J. (author), Schanz, D. (author), Weikert, T. (author), Kirmse, T. (author), Schröder, A. (author)
Multiple optical measurement techniques have been applied for the investigation of a propeller-wing wind tunnel model. The (half) wind tunnel model is equipped with a nine bladed propeller and its wing has active Coanda blowing over the whole span of the wing. The aim of the investigation is to gain understanding of the flow phenomena,...
conference paper 2013
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Ceglia, G. (author), Violato, D. (author), Tuinstra, M. (author), Scarano, F. (author)
An investigation on the compressibility effects arising into the near field of turbulent jets operated at high Reynolds number at Mach numbers M=0.3, 0.9 and 1.1 (under-expanded regime) is carried out with two-components planar PIV experiments with high resolution cameras. The arrangement of the PIV system allows for mapping out the flow field...
conference paper 2013
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Morton, C. (author), Yarusevych, S. (author)
The present study investigates two techniques for phase averaging time resolved two-dimensional PIV measurements for the purpose of extracting dominant three-dimensional wake characteristics. The first one is the classical phase averaging which uses a reference wake velocity signal measured via Laser Doppler Velocimetry (LDV). The second...
conference paper 2013
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