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Your search keyword '"Dai, Saishuai"' showing total 43 results
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43 results on '"Dai, Saishuai"'

17. Unsteady hydrodynamics of a surface piercing and fully submerged body when entering a lock.

Author

Liu, Yihan, Zhao, Guangwei, Terziev, Momchil, Dai, Saishuai, Feng, Aichun, and Yuan, Zhi-Ming

Subjects
SHIP hydrodynamics, FREE surfaces, SUBMERGED structures, HYDRODYNAMICS, WATERWAYS, BOUNDARY value problems, TOWING
Abstract

Ship hydrodynamics in a constant waterway have been well studied. With a coordinate system fixed on the moving ship, the boundary value problem (BVP) is usually treated as a steady one. However, the hydrodynamics of a ship moving in confined waterways with abrupt changes in width or depth are complex due to their unsteady nature. The studies on such unsteady problems are insufficient. In the engineering practice, the hydrodynamic unsteadiness can be fully reflected by a scenario when a ship enters a lock. Prior studies have predominantly focused on predicting the ships' hydrodynamic forces without considering the unsteady terms on the free-surface boundary conditions. Obviously, such steady or quasi-steady methods overlooked the crucial unsteady phenomena on free water surface. To address this gap, the present study introduces a novel three-level difference scheme to discretize the free surface condition, preserving unsteady terms while maintaining temporal continuity of cells on the free surface. With the implementation of such fully unsteady BVP, we observed some interesting unsteady free surface motions, which were not well documented in the existing literature. To verify our new observations, as well as to validate the numerical method proposed in this study, two physical model tests were designed and conducted in a towing tank: a submerged ellipsoid enters a deep lock at relatively high speeds, and a box enters a shallow and narrow lock at very low speeds. The discussion is highlighted on the unsteady waves in front of the moving bodies, as well as the unsteady resistance induced by such waves. [ABSTRACT FROM AUTHOR]

Published
2024
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24. Assessing the performance of an oscillating water column type wave energy device

Author

Dai, Saishuai

Subjects
621.31
Abstract

To meet the need of clean energy, a variety of renewable energy technologies have been developed. Among those, wave energy stands out for its outstanding merits. For instance, wave energy is clean, renewable, has high energy intensity and long resource available time. However, due to the short development history of wave energy technologies, the cost of wave energy is too high compared with the other renewable energy technologies. As well as lack of cost effective Wave Energy Converters (WECs) scenarios, another reason that keeps the cost of wave energy high is that the performance of a WECs may not be accurately assessed during its design and development stage. This leads to error in estimating the cost of energy produced by the full scale device. Therefore, this study aims to drive the cost of WECs down by investigating several major aspects that will bias the assessing of the performance of a WEC during the design and development stage. Literature review suggested the uncertainty in the measurement, the tank width effect (in tank testing), the performance of the simulated simple Power Take Off (PTO) and the scale effect are major aspects that bias the assessment. By tank testing and Computational Fluid Dynamic (CFD) simulation, the above three aspects were investigated. It is found that the uncertainty in the measurement leads to an uncertainty in the power captured at model scale about 5% around the peak output. The appearance of the tank wall will over estimate the performance of a single unit depending on the width of the tank. A 1 : 150th scaled (of the full scale.) device may under estimate the performance of the device by about 34% compared with a 1 : 16.67th scaled device, while a 1 : 50th scaled device under estimate the performance of a 1 : 16.67th scaled device by 6.6%. The CFD simulation demonstrated its advantage over the tank testing when scaling and tank width effect is concerned. Therefore, to better estimate the performance, the assessment shall be carried out by both experiment and numerical simulation. Based on the study carried out, recommendation and guide line for tank testing of a FSCOWC device was given at the end of the thesis.

Published
2016
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38. A Heuristic Approach for Inter-Facility Comparison of Results from Round Robin Testing of a Floating Wind Turbine in Irregular Waves

Author

Gueydon, Sebastien, primary, Judge, Frances, additional, Lyden, Eoin, additional, O’Shea, Michael, additional, Thiebaut, Florent, additional, Le Boulluec, Marc, additional, Caverne, Julien, additional, Ohana, Jérémy, additional, Bouscasse, Benjamin, additional, Kim, Shinwoong, additional, Day, Sandy, additional, Dai, Saishuai, additional, and Murphy, Jimmy, additional

Published
2021
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39. Round Robin Laboratory Testing of a Scaled 10 MW Floating Horizontal Axis Wind Turbine

Author

Gueydon, Sebastien, primary, Judge, Frances M., additional, O’Shea, Michael, additional, Lyden, Eoin, additional, Le Boulluec, Marc, additional, Caverne, Julien, additional, Ohana, Jérémy, additional, Kim, Shinwoong, additional, Bouscasse, Benjamin, additional, Thiebaut, Florent, additional, Day, Sandy, additional, Dai, Saishuai, additional, and Murphy, Jimmy, additional

Published
2021
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