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Valori, V. (author), Elsinga, G.E. (author), Rohde, M. (author), Westerweel, J. (author), van der Hagen, T.H.J.J. (author)
Abstract: The feasibility of particle image velocimetry (PIV) in a thermally convective supercritical fluid was investigated. Hereto a Rayleigh–Bénard convection flow was studied at pressure and temperature above their critical values. The working fluid chosen was trifluoromethane because of its experimentally accessible critical point. The...
journal article 2019
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Benschop, H.O.G. (author), Greidanus, A.J. (author), Delfos, R. (author), Westerweel, J. (author), Breugem, W.P. (author)
We investigate the deformation of a linear viscoelastic compliant coating in a turbulent flow for a wide range of coating parameters. A one-way coupling model is proposed in which the turbulent surface stresses are expressed as a sum of streamwise-travelling waves with amplitudes determined from the stress spectra of the corresponding flow...
journal article 2019
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Grift, E.J. (author), Vijayaragavan, N. B. (author), Tummers, M.J. (author), Westerweel, J. (author)
We present results on the drag on, and the flow field around, a submerged rectangular normal flat plate, which is uniformly accelerated to a constant target velocity along a straight path. The plate aspect ratio is chosen to be to resemble an oar blade in (competitive) rowing, the sport which inspired this study. The plate depth, i.e. the...
journal article 2019
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Lintmeijer, Lotte L. (author), Onneweer, John P.T. (author), Hofmijster, Mathijs J. (author), Wijgergangs, Willem A. (author), De Koning, Hans (author), Clairbois, Bert (author), Westerweel, J. (author), Grift, E.J. (author), Tummers, M.J. (author)
To analyze on-water rowing performance, a valid determination of the power loss due to the generation of propulsion is required. This power los can be calculated as the dot product of the net water force vector ( <sup>~</sup> F <sub>w;o</sub> ) and the time derivative of the position vector of the point at the blade where <sup>~</sup> F <sub...
journal article 2019
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Goyens, J. (author), Pourquie, M.J.B.M. (author), Poelma, C. (author), Westerweel, J. (author)
The vestibular system in the inner ear senses angular head manoeuvres by endolymph fluid which deforms a gelatinous sensory structure (the cupula). We constructed computer models that include both the endolymph flow (using CFD modelling), the cupula deformation (using FEM modelling), and the interaction between both (using fluid–structure...
journal article 2019
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Muller, K. (author), Tam, D.S.W. (author), Westerweel, J. (author)
Obtaining accurate experimental data from Lagrangian tracking and tomographic velocimetry requires an accurate and consistent camera calibration over multiple views. At length-scales that span beyond the laboratory environment obtaining a camera calibration can be challenging. Combining tools developed in computer vision and non-linear camera...
conference paper 2018
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Eisma, H.E. (author), Tam, D.S.W. (author), Westerweel, J. (author), van de Water, W. (author)
We present results on the analysis of measurements on the dispersion of a contaminant in a turbulent boundary layer. The contaminant is a fluorescent dye (Rh.-B) that was introduced in a turbulent boundary layer (푅푅푒푒# = 3050) in a water channel. The velocity field was measured by means of tomographic PIV. Simultaneously, the concentration field...
conference paper 2018
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Gül, M. (author), Elsinga, G.E. (author), Westerweel, J. (author)
This paper describes the hysteresis in the torque for Taylor–Couette flow in the turbulent flow regime for different shear Reynolds numbers, aspect ratios and boundary conditions. The hysteresis increases with decreasing shear Reynolds number and becomes more pronounced as the aspect ratio is increased from 22 to 88. Measurements conducted in...
journal article 2018
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Kislaya, A. (author), Deka, Antaran (author), Veenstra, Peter (author), Tam, D.S.W. (author), Westerweel, J. (author)
In micro-PIV, reaching the optimum image density has always been difficult due to high displacement gradient, coagulation of particles at the inlet and due to particles adhering to the surface to name a few. The most widely used method is to take ensemble correlation average of multiple PIV images to extract the velocity field. However, this...
conference paper 2018
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Gotfredsen, Erik (author), Kunoy, Jens D. (author), Mayer, Stefan (author), Poelma, C. (author), Westerweel, J. (author), Meyer, Knud Erik (author)
The effect of pulsations in a catalyst converter is investigated with the aim of determining if a steady flow captures the same physical phenomena as the pulsating flow. For this specific case, guide vanes are mounted in the sudden expansion to obtain a uniform inlet flow to the catalytic layers. The test rig is successfully validated against...
conference paper 2018
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van Eckeveld, A.C. (author), Gotfredsen, E. (author), Westerweel, J. (author), Poelma, C. (author)
Two-phase flow in ribbed or corrugated pipes is of interest in many industrial applications. Experiments are performed to assess the flow regime characteristics in upward annular flow through vertical smooth and corrugated pipes. From high speed recordings, the flow regime and temporal film characteristics are obtained. A novel implementation...
journal article 2018
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Eisma, H.E. (author), Tomas, J.M. (author), Pourquie, M.J.B.M. (author), Elsinga, G.E. (author), Jonker, H.J.J. (author), Westerweel, J. (author)
Simultaneous particle-image velocimetry and laser-induced fluorescence combined with large-eddy simulations are used to investigate the flow and pollutant dispersion behaviour in a rural-to-urban roughness transition. The urban roughness is characterized by an array of cubical obstacles in an aligned arrangement. A plane fence is added one...
journal article 2018
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Cornel, W.A. (author), Westerweel, J. (author), Poelma, C. (author)
The challenge presented in this research is to determine the local volumetric bubble concentration (or void fraction) in the center of a microbubble cloud with limited optical access and without disturbing the flow. By applying defocused volumetric shadowgraphy to an aerated water column we were able to measure the characteristics of single...
conference paper 2018
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van Hout, R.L.H. (author), Eisma, H.E. (author), Elsinga, G.E. (author), Westerweel, J. (author)
In many applications, finite-sized particles are immersed in a turbulent boundary layer (TBL) and it is of interest to study wall effects on the instantaneous shedding of turbulence structures and associated mean velocity and Reynolds stress distributions. Here, 3D flow field dynamics in the wake of a prototypical, small sphere (D+=50, 692&lt...
journal article 2018
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van Meerkerk, M. (author), Poelma, C. (author), Westerweel, J. (author)
A quasi three-dimensional stereo-camera measurement technique has been devised that is able to measure liquid free surface profiles, by scanning a light sheet. The technique will be applied to study the variability of impact pressure observed during wave impact in a newly developed experimental set-up. The set-up imposes severe optical (single...
conference paper 2018
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van Houwelingen, Josje (author), Antwerpen, Raf M. (author), Holten, Ad P.C. (author), Grift, E.J. (author), Westerweel, J. (author), Clercx, Herman J.H. (author)
In this paper a video-based method to automatically track instantaneous velocities of a swimmer is presented. Single cameras were used to follow a marker (LED) attached to the body. The method is inspired by particle tracking techniques, traditionally used in the field of fluid dynamics, to measure local velocities of a fluid flow. During the...
journal article 2018
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Charruault, F.T. (author), Greidanus, A.J. (author), Breugem, W.P. (author), Westerweel, J. (author)
The present study introduces an experimental technique based on a Free Surface-Synthetic Schlieren (FS-SS) method in order to characterize free surfaces subjected to strong deformations. Current synthetic Schlieren methods are based on local image correlation and thus limited to rather weak image deformations, implying that they can only resolve...
conference paper 2018
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Tomas, J.M. (author), Eisma, H.E. (author), Pourquie, M.J.B.M. (author), Elsinga, G.E. (author), Jonker, H.J.J. (author), Westerweel, J. (author)
Both large-eddy simulations (LES) and water-tunnel experiments, using simultaneous stereoscopic particle image velocimetry and laser-induced fluorescence, have been used to investigate pollutant dispersion mechanisms in regions where the surface changes from rural to urban roughness. The urban roughness was characterized by an array of...
journal article 2017
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van Eckeveld, A.C. (author), Westerweel, J. (author), Poelma, C. (author)
When a corrugated pipe is subject to a dry gas flow, high amplitude sound can be produced (so-called ‘whistling’). It was shown previously that liquid addition to corrugated pipe flow has the ability to reduce sound production. Small amounts of liquid are sufficient to mitigate whistling entirely. One of the mitigation mechanisms, cavity...
journal article 2017
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Valori, V. (author), Elsinga, G.E. (author), Rohde, M. (author), Tummers, M.J. (author), Westerweel, J. (author), van der Hagen, T.H.J.J. (author)
journal article 2017
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