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Tan, J. (author), Polinder, H. (author), Jarquin Laguna, A. (author), Miedema, S.A. (author)An adjustable draft point absorber was recently proposed as a novel approach to improve power absorption with constrained power take-off (PTO) capacities. The key feature of the novel wave energy converter (WEC) concept is to adjust the buoy draft by regulating the ballast water inside the buoy, which aims to enable variation of the natural...journal article 2023
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Tan, J. (author), Tao, W. (author), Jarquin Laguna, A. (author), Polinder, H. (author), Xing, Yihan (author), Miedema, S.A. (author)Wave-to-Wire models play an important role in the development of wave energy converters. They could provide insight into the complete operating process of wave energy converters, from the power absorption stage to the power conversion stage. In order to cover a set of relevant nonlinear effects, wave-to-wire models are predominately...journal article 2023
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Tan, J. (author), Wang, X. (author), Polinder, H. (author), Jarquin Laguna, A. (author), Miedema, S.A. (author)A crucial part of wave energy converters (WECs) is the power take-off (PTO) mechanism, and PTO sizing has been shown to have a considerable impact on the levelized cost of energy (LCOE). However, as a dominating type of PTO system in WECs, previous research pertinent to PTO sizing did not take modeling and optimization of the linear permanent...journal article 2022
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Tan, J. (author), Polinder, H. (author), Jarquin Laguna, A. (author), Miedema, S.A. (author)The Power Take-Off (PTO) rating of Wave Energy Converters (WECs) is generally much higher than the average extracted power. Scientific literature has indicated that downsizing the PTO capacity to a suitable level is beneficial for improving the techno-economic competitiveness. In this paper, a novel design, namely the adjustable draft system,...journal article 2022
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Tan, J. (author), Polinder, H. (author), Jarquin Laguna, A. (author), Miedema, S.A. (author)The power take-off (PTO) system is a main component in wave energy converters (WECs), and it accounts for a notable proportion in the total cost. Sizing the PTO capacity has been proven to be significant to the cost-effectiveness of WECs. In the numerical modeling, the PTO size is normally represented by a force constraint. Therefore, to...journal article 2022
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Tan, J. (author), Polinder, H. (author), Jarquin Laguna, A. (author), Wellens, P.R. (author), Miedema, S.A. (author)Currently, the techno-economic performance of Wave Energy Converters (WECs) is not competitive with other renewable technologies. Size optimization could make a difference. However, the impact of sizing on the techno-economic performance of WECs still remains unclear, especially when sizing of the buoy and Power Take-Off (PTO) are considered...journal article 2021
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Qian, Yi’Nan (author), Wang, Yuanshun (author), Fang, Zhenlong (author), Chen, X. (author), Miedema, S.A. (author)A jet pump is used to transport a variety of working media and is especially suitable for dredged soil transporting. In this study, a three-dimensional numerical study of a jet pump that is used for slurry delivery was carried out. The characteristics of the internal flow field of the mixing chamber with different working parameters were...journal article 2021
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Tan, J. (author), Wang, X. (author), Jarquin Laguna, A. (author), Polinder, H. (author), Miedema, S.A. (author)Downsizing the Power Take-off (PTO) rating has been proven to be beneficial for decreasing the Levelized Cost of Energy (LCOE) of wave energy converters (WECs). However, the linear permanent magnet (PM) generator has not yet been modelled and optimized in detail in previous feasibility studies. This paper extends the study of the PTO...conference paper 2021
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Miedema, S.A. (author)In dredging, trenching, (deep sea) mining, drilling, tunnel boring and many other applications, sand, clay or rock has to be excavated.The book covers horizontal transport of settling slurries (Newtonian slurries). Non-settling (non-Newtonian) slurries are not covered.book 2019
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Miedema, S.A. (author)In dredging, trenching, (deep sea) mining, drilling, tunnel boring and many other applications, sand, clay or rock has to be excavated. This book gives an overview of cutting theories. It starts with a generic model, which is valid for all types of soil (sand, clay and rock) after which the specifics of dry sand, water saturated sand, clay,...book 2019
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Miedema, S.A. (author)In dredging, production estimating is carried out mainly with analytical physical models of the different dredging processes. Slurry transport of settling slurries and cutting processes in sand, clay and rock are already covered in two other books by the author. Other processes like hopper sedimentation and erosion, water jet fluidization,...book 2019
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Xiong, T. (author), Xinzhuo, Zhang (author), Miedema, S.A. (author), Chen, X. (author)Slurry transport is a very important means of transporting solids through a pipeline. To improve the efficiency of slurry transport, especially in coarse particle transport, which is subject to problems such as strong resistance and easy blockage, more of the internal structure of the flow must be known. Empirical and analytical models are...journal article 2019
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Miedema, S.A. (author)Different approaches are present in literature for slurry transport in inclined pipes. Most models assume that the socalled solids effect, the hydraulic gradient of the mixture minus the hydraulic gradient of the carrier liquid, has to be multiplied by the cosine of the inclination angle to a certain power. These powers vary from 0.25 to 1.7. In...conference paper 2017
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Miedema, S.A. (author)Most concentration distribution models are based on the advection diffusion equation for two-dimensional (2D) channel flow. These models may or may not incorporate hindered settling based on the cross-sectional averaged spatial volumetric concentration. These models also use a diffusivity based on the turbulent momentum diffusivity, sometimes...conference paper 2017
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Miedema, S.A. (author)In slurry transport there are many models for fine, medium and coarse particles, based on the assumption that the particles are still small compared to the pipe diameter. However, when the particle size is not small compared to the pipe diameter (up to 25% of the pipe diameter) the models do not give a good prediction of the hydraulic gradient....conference paper 2017
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Miedema, S.A. (author)Most methods for determining the hydraulic gradient of slurry transport are based on a single particle size. A few methods describe how to deal with a graded Particle Size Distribution (PSD). The way these methods deal with graded PSD's is very different. The original Durand/Condolios method defines an equivalent particle diameter, based on a...poster 2017
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Miedema, S.A. (author)In dredging, trenching, (deep sea) mining, drilling, tunnel boring and many other applications, sand, clay or rock has to be excavated. After the soil has been excavated it is usually transported hydraulically as a slurry over a short (TSHD’s) or a long distance (CSD’s). Estimating the pressure losses and determining whether or not a bed will...book 2016
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Miedema, S.A. (author)Models for modeling slurry flow present difficulties on long lines with large pipe diameters and with broad graded sands or gravels. In order to get more insight into the slurry flow process, the Delft Head Loss & Limit Deposit Velocity Framework has been developed that integrates the 5 main flow regimes of slurry transport: fixed or...journal article 2016
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Miedema, S.A. (author), Ramsdell, R.C. (author)In slurry transport of settling slurries in Newtonian fluids, it is often stated that one should apply a line speed above a critical velocity, because blow this critical velocity there is the danger of plugging the line. There are many definitions and names for this critical velocity. It is referred to as the velocity where a bed starts sliding...journal article 2015
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Chen, X. (author), Miedema, S.A. (author), Van Rhee, C. (author)The increase of world population has been requiring more and more lands for human activities, which is why the world dredging market has been significantly growing up during the past 20 years. In dredging engineering, underwater excavation process is one of the major procedures which involves complicated physics, no matter it is sand, clay or...journal article 2015