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- Engström, Gunnar, et al.
(författare)
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The Swedish CArdioPulmonary BioImage Study : objectives and design
- 2015
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Ingår i: Journal of Internal Medicine. - : Wiley. - 0954-6820 .- 1365-2796. ; 278:6, s. 645-659
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Tidskriftsartikel (refereegranskat)abstract
- Cardiopulmonary diseases are major causes of death worldwide, but currently recommended strategies for diagnosis and prevention may be outdated because of recent changes in risk factor patterns. The Swedish CArdioPulmonarybioImage Study (SCAPIS) combines the use of new imaging technologies, advances in large-scale 'omics' and epidemiological analyses to extensively characterize a Swedish cohort of 30 000 men and women aged between 50 and 64 years. The information obtained will be used to improve risk prediction of cardiopulmonary diseases and optimize the ability to study disease mechanisms. A comprehensive pilot study in 1111 individuals, which was completed in 2012, demonstrated the feasibility and financial and ethical consequences of SCAPIS. Recruitment to the national, multicentre study has recently started.
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| 4. |
- Berchiche, Nabila, 1973, et al.
(författare)
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Numerical computations and comparison to experiments for a propeller in open water condition
- 2006
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Ingår i: Ship Technology Research. ; 53, s. 9-16
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Tidskriftsartikel (refereegranskat)abstract
- Three-dimensional steady RANS computations were carried out to simulate the flow around a conventional propeller operating in open water conditions. The effects of turbulence were modeled using the shear stress transport SST k- model and the influence of the turbulence model was also investigated using the realizable k- model in combination with enhanced-wall treatment as an alternative.The main objective of this study is to predict the flow around the propeller blade particularly around the blade tip. Computational results, which consist of the forces acting on the propeller and velocity distributions downstream the propeller are illustrated and compared with the experimental data obtained from open water tests and PIV measurements for the design advance coefficient J. The thrust and torque coefficients are also compared for several advance numbers. The SST k- model performed well in predicting the performance of the propeller and the main characteristics of the propeller flow.
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| 6. |
- Coslovich, Francesco, 1990, et al.
(författare)
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Added resistance, heave and pitch for the KVLCC2 tanker using a fully nonlinear unsteady potential flow boundary element method
- 2021
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Ingår i: Ocean Engineering. - : Elsevier Ltd. - 0029-8018 .- 1873-5258. ; 229
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, a fully nonlinear unsteady potential flow method is used to predict added resistance, heave and pitch for the KVLCC2 hull in regular head waves at design speed. The method presents a nonlinear decomposition of the velocity potential and the wave field and an adaptive grid refinement. A formulation for the acceleration potential is used to obtain the pressure. To improve computational efficiency, a Barnes-Hut algorithm is introduced. A grid dependency study and a study on the impact of different time steps on the solution are performed. Numerical results have been compared with experimental data for the design speed. A general good agreement is found for added resistance, especially for longer waves. Heave and pitch are properly computed for all wave lengths in the range λ/Lpp=0.4 to 1.4. © 2021 The Author(s)
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| 7. |
- Coslovich, Francesco, 1990, et al.
(författare)
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Computations of roll motion in waves using a fully nonlinear potential flow method
- 2018
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Ingår i: NAV International Conference on Ship and Shipping Research. - 2282-8397. ; , s. 186-193
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Konferensbidrag (refereegranskat)abstract
- Optimization of modern hulls when moving in a seaway puts new demands on the computational methods used. Nonlinear effects become important for wave loads and added resistance in waves in presence of large motions. The purpose of this paper is to present a method which aims to fill the gap between RANSE methods and partly nonlinear panel methods. The method solves the fully nonlinear free surface time-domain potential flow problem including a hull undergoing rigid body motions. Nonlinearities under the hypothesis of potential flow are taken into account, i.e. higher and lower frequency components, hull shape above calm water line and interaction between incoming, radiated, diffracted, reflected and ship generated waves. The potential flow method alone cannot handle roll motion since roll is dominated by viscous effects. Two methods to include roll damping within the potential flow code are used: the first one obtains roll damping coefficients through inertial and geometric characteristics of the ship. The second one uses model test results. Numerical results using both methods are compared. The code has already been tested in head seas. In this paper, numerical simulations of roll decay and roll motion in beam sea are compared to model test results.
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| 8. |
- Coslovich, Francesco, 1990, et al.
(författare)
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Prediction of Parametric Rolling for a Container Ship in Regular and Irregular Waves Using a Fully Nonlinear Time Domain Potential Flow Method
- 2019
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Ingår i: 8th International Conference on Computational Methods in Marine Engineering, MARINE 2019. - 9788494919435 ; , s. 646- 657
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Konferensbidrag (refereegranskat)abstract
- In this paper numerical simulations of parametric rolling have been performed. SAFEDOR, an EU funded benchmark study on the capability of different methods to predict such motion, was replicated here, in order to assess the quality of SHIPFLOW MOTIONS for the evaluation of this phenomenon. The code is a fully nonlinear 3D unsteady potential flow method. Since viscosity is not implicitly accounted for by a potential flow method, two different techniques are used here to introduce viscous damping coefficients in the roll motion equation. The results obtained with this method are aligned with the results from the best performing methods analyzed in the benchmark, showing a satisfactory match with experimental results.
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| 10. |
- Janson, Carl-Erik, 1957, et al.
(författare)
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A comparison of four wave cut analysis methods for wave resistance prediction
- 2004
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Ingår i: Ship Technology Research. ; 51, s. 173-184
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Tidskriftsartikel (refereegranskat)abstract
- Four different techniques that use wave cut analysis to predict the wave pattern resistance coefficient of a ship hull are compared. Two of the techniques are based on longitudinal wave cuts and two are based on transverse wave cuts. The results are compared with values from pressure integration and with towing tank measurements of the residuary resistance. Three hulls are used for the comparison: the Dyne Tanker, the Series 60 and the SSPA Ro-Ro Ship model 2062. The wave cuts are computed from linear and non-linear solutions of the wave pattern.A technique whereby the free surface deformation at any distance downstream of a vessel can be predicted very quickly based on the information computed in one of the transverse wave cut methods is also described.When used with appropriate wave information, the wave resistance prediction was very consistent for the four different wave cut methods and it was not possible say that one method is better than the other in this respect. The four wave cut methods tested gave the same ranking of the wave resistance for a bulb size variation of the Ro-Ro ship model. This ranking agreed with the ranking from pressure integration and from towing tank measurements.The transverse wave cut methods seems to be more robust and needs less time for the CFD calculation than the longitudinal wave cut methods which makes them more suitable to include in an automatic optimisation procedure.Single and multiple transverse wave cuts methods performed equally well for linear computations, but the multiple transverse wave cut method is preferred for non-linear computations since it is less sensitive to the position of the wave cuts.The wave cut analysis calculates values for the wave resistance that are less than the values obtained from pressure integration and from the residuary resistance as measured in a towing tank.
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