| 1. |
- Lee, J. -H, et al.
(författare)
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Comparative study on added resistance of a bulk carrier in regular head and oblique waves
- 2020
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Ingår i: Proceedings of the International Offshore and Polar Engineering Conference. - : International Society of Offshore and Polar Engineers. - 9781880653845 ; , s. 3385-3393
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Konferensbidrag (refereegranskat)abstract
- In this study, a comparative study on motion response and added resistance of a Supramax bulk carrier (K-Supramax Original) in regular waves was carried out to evaluate the reliabilities and accuracies of experimental and numerical simulation techniques. Two kinds of experiments were performed; one is the towing tank model testing for head wave conditions conducted at Seoul National University, and the other is the free-running model test for head and oblique wave conditions conducted at SSPA Sweden AB. Also, nine numerical computation results submitted by seven institutions were compared with the experimental data. The computation results were obtained by various seakeeping analysis methods such as the 2D strip theory, 3D Rankine panel method, and Computational Fluid Dynamics (CFD) based analysis. Based on the comparison, the characteristics of each numerical technique and resultant accuracies of seakeeping analyses were investigated. It was also confirmed that different results were obtained although the same program was used because of the user dependencies; setting for computation parameters, numerical schemes, and mesh generations, etc. Furthermore, the sensitivities of seakeeping quantities with respect to wave amplitudes were examined by conducting both model tests and nonlinear numerical simulations for different wave slopes. Lastly, the tendencies of ship motion and added resistance depending on the heading angle were identified, and the reliabilities of experiments and numerical computations for oblique waves were discussed.
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| 2. |
- Park, D. -M, et al.
(författare)
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Comparative study on added resistance of a container ship in waves
- 2019
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Ingår i: Proceedings of the International Offshore and Polar Engineering Conference. - : International Society of Offshore and Polar Engineers. - 9781880653852 ; , s. 4418-4425
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Konferensbidrag (refereegranskat)abstract
- This paper presents a comparative study on the motion responses and added resistance of a container ship. Eight institutions participated in the comparative study, and ten numerical results were compared with two experimental results. Two experimental results were obtained from Seoul National University towing tank and Sweden SSPA seakeeping basin. The results of two experimental institutions in head sea condition were compared and showed good agreement with each other. The difference in motion responses and added resistance according to the numerical analysis method were compared. Even though the same program was used, it was observed that different results were obtained depending on the users. The comparison of the motion response and the added resistance according to the change of wave slope showed that the added resistance greatly changed according to the wave slope. This tendency was the same in experimental results and CFD analysis results. From the comparative study, the influence of the experiment method on the added resistance, and the characteristics of numerical each code were identified.
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| 3. |
- Boddaert, S., et al.
(författare)
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Fire safety of BIPV : International mapping of accredited and R&D facilities in the context of codes and standards 2023
- 2023
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The objective of Task 15 of the IEA Photovoltaic Power Systems Programme is to create an enabling framework to accelerate the penetration of BIPV products in the global market of renewables, resulting in an equal playing field for BIPV products, BAPV products and regular building envelope components, respecting mandatory issues, aesthetic issues, reliability issues, and financial issues.Subtask E of Task 15 is focused on pre-normative international research on BIPV characterisation methods and activity E.3 is dedicated to fire safety of BIPV modules and installations.
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| 4. |
- Park, D. -M, et al.
(författare)
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Experimental and numerical studies on added resistance of ship in oblique sea conditions
- 2019
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Ingår i: Ocean Engineering. - : Elsevier Ltd. - 0029-8018 .- 1873-5258. ; 186
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, the added resistance of a large tanker is estimated experimentally and numerically in oblique sea. Experiments on ship motion response and added resistance in oblique sea are performed in the SSPA seakeeping basin. The experiments are conducted using the self-propulsion test for seven wave directions between 180° and 0°. In the self-propulsion test, the added resistance is estimated from the difference between the thrust of the propeller in calm water and waves. In the case of the head sea, the results are compared with those obtained from the captive test at the towing test of Seoul National University. As numerical method, two methods are selected: the strip method and the 3D Rankine panel method. The maximum value of the added resistance is observed between the incident wave directions of 180° and 150°. From 120°, the added resistance tends to decrease and the peak of the added resistance shifted to the short waves. Through the two numerical analysis methods, the tendency of added resistance and the cause of the change of the added resistance in the oblique sea are investigated.
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| 5. |
- Kim, Kyung Ho, 1984, et al.
(författare)
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Ambipolar charge transport in quasi-free-standing monolayer graphene on SiC obtained by gold intercalation
- 2020
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Ingår i: Physical Review B. - : American Physical Society. - 2469-9950 .- 2469-9969. ; 102:16
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Tidskriftsartikel (refereegranskat)abstract
- We present a study of quasi-free-standing monolayer graphene obtained by intercalation of Au atoms at the interface between the carbon buffer layer (Bu-L) and the silicon-terminated face (0001) of 4H-silicon carbide. Au intercalation is achieved by deposition of an atomically thin Au layer on the Bu-L followed by annealing at 850 °C in an argon atmosphere. We explore the intercalation of Au and decoupling of the Bu-L into quasi-free-standing monolayer graphene by surface science characterization and electron transport in top-gated electronic devices. By gate-dependent magnetotransport we find that the Au-intercalated buffer layer displays all properties of monolayer graphene, namely gate-tunable ambipolar transport across the Dirac point, but we find no observable enhancement of spin-orbit effects in the graphene layer, despite its proximity to the intercalated Au layer.
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| 6. |
- Kim, Keunjae, et al.
(författare)
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Hydrodynamic optimization of pre-swirl stator by CFD and model testing
- 2013
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Ingår i: International Shipbuilding Progress. - 0020-868X .- 1566-2829. ; 60:1-4, s. 233-276
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Tidskriftsartikel (refereegranskat)abstract
- With environmental concerns becoming one of the most important issues facing the shipping/ship-building industry today, SSPA has witnessed strong demand for the development of energy saving devices (ESD). SSPA anticipates that the demand will be greater to respond to new requirements set by the IMO regulation on energy efficient design index (EEDI). SSPA has been involved in many joint research projects in developing energy saving solutions. Daewoo Shipbuilding and Marine Engineering Co. Ltd. (DSME) has developed several ESDs in cooperation with SSPA, where SSPA has tested most of the ESDs designed by DSME over the last 10 years. The pre-swirl stator (PSS) is a device mounted on the stern boss just upstream of the propeller (see Fig. 6 or Fig. 33). It is designed to generate pre-swirl flow to the propeller in order to gain a favorable interaction with the propeller that improves the propulsive efficiency and results in a power reduction. This paper is a full description of one of the developments of PSS from the early design stage, optimization phase, and confirmation by model tests to validation through sea trial tests.
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| 7. |
- Kramer, Morten, et al.
(författare)
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Highly accurate experimental heave decay tests with a floating sphere : A public benchmark dataset for model validation of fluid–structure interaction
- 2021
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Ingår i: Energies. - : MDPI AG. - 1996-1073. ; 14:2
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Tidskriftsartikel (refereegranskat)abstract
- Highly accurate and precise heave decay tests on a sphere with a diameter of 300 mm were completed in a meticulously designed test setup in the wave basin in the Ocean and Coastal Engineering Laboratory at Aalborg University, Denmark. The tests were dedicated to providing a rigorous benchmark dataset for numerical model validation. The sphere was ballasted to half submergence, thereby floating with the waterline at the equator when at rest in calm water. Heave decay tests were conducted, wherein the sphere was held stationary and dropped from three drop heights: a small drop height, which can be considered a linear case, a moderately nonlinear case, and a highly nonlinear case with a drop height from a position where the whole sphere was initially above the water. The precision of the heave decay time series was calculated from random and systematic standard uncertainties. At a 95% confidence level, uncertainties were found to be very low—on average only about 0.3% of the respective drop heights. Physical parameters of the test setup and associated uncertainties were quantified. A test case was formulated that closely represents the physical tests, enabling the reader to do his/her own numerical tests. The paper includes a comparison of the physical test results to the results from several independent numerical models based on linear potential flow, fully nonlinear potential flow, and the Reynolds-averaged Navier–Stokes (RANS) equations. A high correlation between physical and numerical test results is shown. The physical test results are very suitable for numerical model validation and are public as a benchmark dataset. © 2021 by the authors.
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