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Klapwijk, M.D. (author)
There is increasing attention for the effects of anthropogenic underwater radiated noise (URN) on marine fauna. This is expected to lead to regulations with respect to the maximum permitted sound emissions of ships. It is known that cavitating tip vortices, generated by ship propellers, are some of the key contributors to URN. Consequently,...
doctoral thesis 2021
document
Eling, R.P.T. (author)
In the competitive automotive market, the performance of turbochargers is constantly being pushed towards their theoretical optimum. One of the key components of the turbocharger is the rotor-bearing system, which determines the friction losses and noise output and furthermore affects the overall turbocharger efficiency, reliability and cost. In...
doctoral thesis 2018
document
Dash, A. (author), Jahangir, S. (author), Poelma, C. (author)
A quantitative analysis of two imaging modalities, shadowgraphy and x-ray imaging, is presented in the framework of void fraction determination. The need for this arises from the fact that shadowgraphs are sometimes utilized to quantify void fraction profiles, which is an unproven method. Time-averaged x-ray images are used to evaluate the...
journal article 2018
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Pennings, P.C. (author)
This thesis describes the mechanisms with which tip vortex cavitation is responsible for broadband pressure fluctuations on ship propellers. Hypotheses for these are described in detail by Bosschers (2009). Validation is provided by three main cavitation-tunnel experiments, one on a model propeller and two on a stationary wing. These have...
doctoral thesis 2016
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Pennings, P.C. (author), Westerweel, J. (author), Van Terwisga, T.J.C. (author)
The goal of this study is to test the hypothesis that the resonance of a tip vortex cavity is responsible for high-amplitude broadband pressure-fluctuations, typically between 40 and 70 Hz,Hz, for a full scale propeller. This is achieved with a model propeller in a cavitation tunnel. Simultaneous high-speed video shadowgraphy and sound...
journal article 2016
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Mani, K.V. (author), Cervone, A. (author), Hickey, J.P. (author)
This paper presents a dynamic system approach for the modeling of fluid flow in microchannels to be used in thrust control applications. A micro-resistojet fabricated using MEMS (Microelectromechanical Systems) technology has been selected for the analysis. The device operates by vaporizing a liquid propellant, in this case water, and expelling...
conference paper 2016
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Eling, R.P.T. (author), te Wierik, M. (author), van Ostayen, R.A.J. (author), Rixen, D.J. (author)
Journal bearings are used to support rotors in a wide range of applications. In order to ensure reliable operation, accurate analyses of these rotor-bearing systems are crucial. Coupled analysis of the rotor and the journal bearing is essential in the case that the rotor is flexible. The accuracy of prediction of the model at hand depends on its...
journal article 2016
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Örley, F. (author), Trummler, T. (author), Hickel, S. (author), Mihatsch, M.S. (author), Schmidt, S.J. (author), Adams, N.A. (author)
We employ a barotropic two-phase/two-fluid model to study the primary break-up of cavitating liquid jets emanating from a rectangular nozzle, which resembles a high aspect-ratio slot flow. All components (i.e., gas, liquid, and vapor) are represented by a homogeneous mixture approach. The cavitating fluid model is based on a thermodynamic...
journal article 2015
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Pennings, P.C. (author), Bosschers, J. (author), Westerweel, J. (author), Van Terwisga, T.J.C. (author)
The dynamic behaviour of vortex cavitation on marine propellers may cause inboard noise and vibration, but is not well understood. The main goal of the present study is to experimentally analyse the dynamics of an isolated tip vortex cavity generated at the tip of a wing of elliptical planform. Detailed high-speed video shadowgraphy was used to...
journal article 2015
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Alakhramsing, S. (author), Van Ostayen, R.A.J. (author), Eling, R.P.T. (author)
Accurate prediction of cavitation is an important feature in hydrodynamic bearing modeling. Especially for thermo-hydrodynamic modeling, it is crucial to use a mass-conservative cavitation algorithm. This paper introduces a new mass-conserving Reynolds cavitation algorithm, which provides fast convergence and easy implementation in finite...
journal article 2015
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Liu, Y. (author), Salemink, H.W.M. (author)
A highly sensitive sensor design based on two-dimensional photonic crystal cavity is demonstrated. The geometric structure of the cavity is modified to gain a high quality factor, which enables a sensitive refractive index sensing. A group of slots with optimized parameters is created in the cavity. The existence of the slots enhances the light...
journal article 2015
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Pereira, S.P. (author), Vuik, K. (author), Pinho, F.T. (author), Nobrega, J.M. (author)
The present work explores the massively parallel capabilities of the most advanced architecture of graphics processing units (GPUs) code named “Fermi”, on a two-dimensional unstructured cell-centred finite volume code. We use the SIMPLE algorithm to solve the continuity and momentum equations that was fully ported to the GPU. The benefits of...
conference paper 2013
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Ahn, Byoung-Kwon (author), Lee, Tea-Kwon (author), Kim, Hyoung-Tae (author), Lee, Chang-Sup (author)
journal article 2012
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Atamanenko, T.V. (author)
This thesis deals with grain refinement under the influence of ultrasonic-driven cavitation in aluminium casting processes. Three major goals of this research were: (1) to identify the mechanism of the cavitation-aided grain refinement at different stages of solidification; (2) to reveal the conditions of the stable grain refinement effect in...
doctoral thesis 2010
document
Vrijdag, A. (author)
Off design conditions can have a severe impact on ship propulsion system behaviour. Resistance increase for instance leads to a higher engine loading, and can also easily lead to a decrease of cavitation inception speed with respect to calm water conditions. Wakefield variations due to ship motions, waves and manoeuvres also have effect on...
doctoral thesis 2009
document
Vrijdag, A. (author)
conference paper 2009
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Foeth, E.J. (author)
doctoral thesis 2008
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Fureby, C. (author)
The present study concerns the application of Large Eddy Simulation (LES) and Implicit LES (ILES) to engineering flow problems. Such applications are often very complicated, involving both complex geometries and complex physics, such as turbulence, chemical reactions, phase changes and compressibility. The aim of the study is to illustrate what...
conference paper 2006
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Niu, Y.Y. (author), Lin, Y.C. (author)
In this paper, a modification of pressure-velocity diffusion terms in AUSMDV is proposed to compute the compressible cavitated liquid-gas flows. As we know, cavitation phenomena are widely seen in multi-phase flow with different sizes of time and length scale. An accurate resolution of multi-scale phenomena such as material interfaces, contact...
conference paper 2006
document
Schmidt, S.J. (author), Sezal, I.H. (author), Schnerr, G.H. (author)
The present paper focuses on a numerical approach based on the Riemann problem to simulate liquid flows with phase changes. Thereby, the flow properties include velocities from O(1) m/s to O(100) m/s and pressures from p approx 0 bar to O(1000) bar. The thermal and caloric behavior of liquid and vapor will be described by suitable equations of...
conference paper 2006
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