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Possenti, Luca (author), de Nooijer, Lennart (author), de Jong, Christ (author), Lam, Frans Peter (author), Beelen, Simon (author), Bosschers, Johan (author), van Terwisga, T.J.C. (author), Stigter, Marinus (author), Reichart, Gert Jan (author)Since the industrial revolution the ocean has become noisier. The global increase in shipping is one of the main contributors to this. In some regions, shipping contributed to an increase in ambient noise of several decibels, especially at low frequencies (10 to 100 Hz). Such an increase can have a substantial negative impact on fish,...review 2024
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Melissaris, Themistoklis (author), Schenke, Sören (author), van Terwisga, T.J.C. (author)A novel cavitation erosion risk model, developed by Schenke et al. ["On the relevance of kinematics for cavitation implosion loads,"Phys. Fluids 31, 052102 (2019)], is applied to compute the cavitation implosion loads. The instantaneous energy balance during the collapse of cavitating structures is considered, where the initial potential...journal article 2023
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Melissaris, Themistoklis (author), Schenke, S. (author), Bulten, Norbert (author), van Terwisga, T.J.C. (author)Propeller cavitation erosion prediction at an early design stage is becoming more and more important since it is one of the key constraints in the search for maximum propeller efficiency. Despite the experience from model tests, cavitation erosion research on actual ship scale is very limited. In this study, an attempt is made to assess the...journal article 2022
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Doijode, P.S. (author), Hickel, S. (author), van Terwisga, T.J.C. (author), Visser, K. (author)We propose and analyse an optimization method that uses a machine learning approach to solve multi-objective, constrained propeller optimization problems. The method uses an online learning strategy where explainable supervised classifiers learn the location of the Pareto front and advise search strategies. The classifiers are trained with...journal article 2022
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Nikolaidou, Lina (author), Laskari, A. (author), Poelma, C. (author), van Terwisga, T.J.C. (author)An air layer within a liquid turbulent boundary layer (TBL) is formed by controlled air injection underneath a flat plate. The incoming boundary layer as well as the flow around the air layer were measured with planar particle image velocimetry (PIV). The effect of different incoming liquid flow characteristics on the air layer geometry is...conference paper 2022
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Doijode, P.S. (author), Hickel, S. (author), van Terwisga, T.J.C. (author), Visser, K. (author)This paper introduces a machine learning approach for optimizing propellers. The method aims to improve the computational cost of optimization by reducing the number of evaluations required to find solutions. This is achieved by directing the search towards design clusters with good performance, i.e. high propulsive efficiency and low...journal article 2022
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Nanda, S. (author), Westerweel, J. (author), van Terwisga, T.J.C. (author), Elsinga, G.E. (author)Following their inception, vortex cavities emanating from stationary wing tips in cavitation tunnels are often observed to grow. These effects are usually attributed to the free and dissolved non-condensable gases in the liquid. However, a detailed mechanism for the cavity's growth is not known. Consequently, the repeatability of vortex...journal article 2022
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Klapwijk, M.D. (author), Lloyd, T. (author), Vaz, G. (author), van Terwisga, T.J.C. (author)The Delft Twist 11 Hydrofoil is a common test case for investigating the interaction between turbulence and cavitation modelling in computational fluid dynamics. Despite repeated investigations, results reported for the lift and drag coefficient are accompanied by significant uncertainties, both in experimental and numerical studies. When...journal article 2021
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Melissaris, Themistoklis (author), Schenke, S. (author), Bulten, Norbert (author), van Terwisga, T.J.C. (author)Predicting the cavitation impact loads on a propeller surface using numerical tools is becoming essential, as the demand for more efficient designs, stretched to the limit, is increasing. One of the possible design limits is governed by cavitation erosion. The accuracy of estimating such loads, using a URANS approach, has been investigated....journal article 2020
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Klapwijk, M.D. (author), Lloyd, T. (author), Vaz, G. (author), van Terwisga, T.J.C. (author)Different variable resolution turbulence modelling approaches (Hybrid, Bridging models and LES) are evaluated for turbulent channel flow at Re<sub>τ</sub>=395, for cases using either streamwise periodic boundary conditions or a synthetic turbulence generator. The effect of iterative, statistical and discretisation errors is investigated. For...journal article 2020
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Klapwijk, M.D. (author), Lloyd, Thomas (author), Vaz, Guilherme (author), van Terwisga, T.J.C. (author)<br/>conference paper 2019
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Schenke, S. (author), van Terwisga, T.J.C. (author)A new technique is proposed in this study to assess the erosive aggressiveness of cavitating flows from numerical flow simulations. The technique is based on the cavitation intensity approach by Leclercq et al. (2017), predicting the instantaneous surface impact power of collapsing cavities from the potential energy hypothesis (see Hammitt,...journal article 2019
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Schenke, S. (author), Melissaris, Themistoklis (author), van Terwisga, T.J.C. (author)This study presents a novel physical model to convert the potential energy contained in vaporous cavitation into local surface impact power and an acoustic pressure signature caused by the violent collapse of these cavities in a liquid. The model builds on an analytical representation of the solid angle projection approach by Leclercq et al. ...journal article 2019
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Melissaris, Themistoklis (author), Bulten, Norbert (author), van Terwisga, T.J.C. (author)In the maritime industry, cavitation erosion prediction becomes more and more critical, as the requirements for more efficient propellers increase. Model testing is yet the most typical way a propeller designer can, nowadays, get an estimation of the erosion risk on the propeller blades. However, cavitation erosion prediction using...journal article 2019
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Melissaris, Themistoklis (author), Bulten, Norbert (author), van Terwisga, T.J.C. (author)Cavitation occurrence on the propeller blades may have severe effects, such as cavitation noise, vibrations in the aft ship, and material damage on propellers or rudder. While noise and vibrations affect comfort and stability, cavitation erosion might lead to a significant reduction of the propeller efficiency and structural integrity....conference paper 2018
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Schenke, S. (author), van Terwisga, T.J.C. (author)The erosive aggressiveness of idealized cavities collapsing on a flat surface is investigated by numerical simulation, employing the cavitation intensity approach by Leclercq et al (2017) as a measure of the local energy impact rate. We propose a more straight forward formulation of the cavitation intensity model and verify that it satisfies...conference paper 2018
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Schenke, S. (author), van Terwisga, T.J.C. (author)Recent studies have indicated that mass transfer models are able to correctly reflect the sheet cavitation dynamics of inertia driven flows, given that the mass transfer model constants governing the source term magnitude are sufficiently large (Koukouvinis and Gavaises 2015) and that enough temporal resolution is provided (Schenke and Van...conference paper 2017
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Schenke, S. (author), van Terwisga, T.J.C. (author)The effect of finite mass transfer rate in combination with temporal resolution on the dynamics of caviting flows is subject of this study. It will be shown that global flow quantities exhibit convergent behaviour with respect to mass transfer rate and time step size in incompressible pressurebased simulation of cavitating flows. It is concluded...conference paper 2017
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- Rotte, G. (author), Zverkhovskyi, O. (author), Kerkvliet, M. (author), van Terwisga, Tom (author) conference paper 2016
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Schenke, S. (author), van Terwisga, T.J.C. (author)One of the key aspects classifying the various approaches in numerical simulation of cavitating flows is the equilibrium flow assumption. It states that internal processes in the flow always occur instantaneously compared to the time scale of the flow (s. Sezal (2009)). As a consequence, the density-pressure trajectory in a barotropic flow may...conference paper 2016