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Cornel, W.A. (author), Westerweel, J. (author), Poelma, C. (author)
Abstract: A novel experimental imaging-based method is presented for the non-intrusive determination of shock wave characteristics (i.e. shock wave speed and magnitude, and shock-induced liquid velocity) in a bubbly flow solely from gas bubble velocities. Shock wave speeds are estimated by the relative motion between gas bubbles at two...
journal article 2023
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van Meerkerk, M. (author), Poelma, C. (author), Hofland, Bas (author), Westerweel, J. (author)
We present an experimental study on the gas flow field development over a plunging breaking wave prior to impact on a vertical wall. The variability of wave impact pressure over repeated measurements is well known (Bagnold, 1939). The formation of instabilities on the wave crest are postulated to be the main source of impact pressure variability...
journal article 2022
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van Eckeveld, A.C. (author), Westerweel, J. (author), Poelma, C. (author)
Severe vibrations and sound production can occur in dry gas flow through corrugated pipes. The addition of very small amounts of liquid to the dry gas flow potentially mitigates these flow-induced vibrations (FIVs) and noise. The different mechanisms behind this whistling mitigation are studied in this work, where acoustic measurements are...
journal article 2020
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van Meerkerk, M. (author), Poelma, C. (author), Hofland, Bas (author), Westerweel, J. (author)
We present an experimental study on the variation in wave impact location and present a mechanism for the development of free surface instabilities on the wave crest for repeatable plunging wave impacts on a vertical wall. The existence of free surface instabilities on an impacting wave is well known, but their characteristics and formation...
journal article 2020
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van Meerkerk, M. (author), Poelma, C. (author), Westerweel, J. (author)
In this work, we extend a planar laser-induced fluorescence method for free surface measurements to a three-dimensional domain using a stereo-camera system, a scanning light sheet, and a modified self-calibration procedure. The stereo-camera set-up enables a versatile measurement domain with self-calibration, improved accuracy, and redundancy...
journal article 2020
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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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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 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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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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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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Van Eckeveld, A.C. (author), Pancham, A.K. (author), Westerweel, J. (author), Poelma, C. (author)
Experiments have been carried out to investigate the effect of liquid cavity filling on the behavior of the gas flow over a flat plate cavity. PIV measurements in the gas phase reveal that cavity filling can affect vortex shedding in the cavity mouth. Shear layer vortices can break-up into smaller vortices, thereby losing their periodic...
conference paper 2015
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Experiments have been carried out to investigate the effect of liquid cavity filling on the behavior of the gas flow over a flat plate cavity. PIV measurements in the gas phase reveal that cavity filling can affect vortex shedding in the cavity mouth. Shear layer vortices can break-up into smaller vortices, thereby losing their periodic...
conference paper 2015
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Poelma, C. (author), Franken, M.J.Z. (author), Kim, H. (author), Westerweel, J. (author)
Contact lines are the locations where a gas, liquid and a solid meet. From everyday experience we know that such contact lines can be mobile, for example in the case of a water droplet sliding over a glass surface. However, the continuum description of the flow towards or away from a contact line implies that the forces diverge as one approaches...
conference paper 2014
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Kloosterman, A. (author), Hierck, B. (author), Westerweel, J. (author), Poelma, C. (author)
Since fluid dynamics plays a critical role in vascular remodeling, quantification of the hemodynamics is crucial to gain more insight into this complex process. Better understanding of vascular development can improve prediction of the process, and may eventually even be used to influence the vascular structure. In this study, a methodology to...
journal article 2014
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Franken, M.J.Z. (author), Poelma, C. (author), Westerweel, J. (author)
We describe a novel measurement method to study the contact line of a droplet at nanoscale level. The method is based on Total Internal Reflection Fluorescence Microscopy (TIRFM), which uses an evanescent excitation field produced by total internal reflection of light. The evanescent field depends on the angle of the incident light and has an...
journal article 2013
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Poelma, C. (author), Kloosterman, A. (author), Hierck, B.P. (author), Westerweel, J. (author)
Imaging-based blood flow measurement techniques, such as particle image velocimetry, have become an important tool in cardiovascular research. They provide quantitative information about blood flow, which benefits applications ranging from developmental biology to tumor perfusion studies. Studies using these methods can be classified based on...
journal article 2012
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Elsinga, G.E. (author), Poelma, C. (author), Schröder, A. (author), Geisler, R. (author), Scarano, F. (author), Westerweel, J. (author)
journal article 2012
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Trip, R. (author), Kuik, D.J. (author), Westerweel, J. (author), Poelma, C. (author)
The transitional regime of a sinusoidal pulsatile flow in a straight, rigid pipe is investigated using particle image velocimetry. The main aim is to investigate how the critical Reynolds number is affected by different pulsatile conditions, expressed as the Womersley number and the oscillatory Reynolds number. The transition occurs in the...
journal article 2012
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Schröder, A. (author), Geisler, R. (author), Staack, K. (author), Elsinga, G.E. (author), Scarano, F. (author), Wieneke, B. (author), Henning, A. (author), Poelma, C. (author), Westerweel, J. (author)
Coherent structures and their time evolution in the logarithmic region of a turbulent boundary layer investigated by means of 3D space–time correlations and time-dependent conditional averaging techniques are the focuses of the present paper. Experiments have been performed in the water tunnel at TU Delft measuring the particle motion within a...
journal article 2010
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