| 1. |
- Andersson, Jennie, 1986, et al.
(författare)
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Energy balance analysis of model-scale vessel with open and ducted propeller configuration
- 2018
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Ingår i: Ocean Engineering. - : Elsevier BV. - 0029-8018. ; 167, s. 369-379
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Tidskriftsartikel (refereegranskat)abstract
- This paper focuses on performance analysis of a model scale vessel equipped with an open versus a ducted propeller in self-propulsion using a control volume analysis of energy, applied on Computational Fluid Dynamics (CFD) results. An energy balance analysis decompose the delivered power for each system into internal and turbulent kinetic energy fluxes, i.e. viscous losses, transverse kinetic energy losses, and pressure work and axial kinetic energy fluxes. Such a decomposition can facilitate understanding of system performance and pinpoint enhancement possibilities. For this specific case it is shown that the much higher required power for the ducted propeller configuration to the largest extent is due to higher viscous losses, caused by mainly propeller duct and different rudder configuration. The energy balance analysis is a post-processing tool with the only additional requirement of solving the energy equation, which can be employed with any CFD-code based on commonly available variables.
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| 2. |
- Eslamdoost, Arash, 1982, et al.
(författare)
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A body-force model for waterjet pump simulation
- 2019
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Ingår i: Applied Ocean Research. - : Elsevier BV. - 0141-1187. ; 90
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Tidskriftsartikel (refereegranskat)abstract
- The role of waterjet pump is to generate thrust by increasing the flow head. Details of the flow inside waterjet pump are important when pump performance is of the main interest. However, in waterjet self-propulsion, pump induced effects are of the main interest rather than the details of the flow inside the pump. This permits sim- plification of pump models when using numerical methods for simulating the flow. In order to find a robust and yet accurate pump model suitable for Computational Fluid Dynamics based methods, models of different so- phistication level are studied in this paper. First, a Sliding Mesh approach, which is capable of capturing the flow details, is validated against a set of cavitation tunnel measurements. Then a series of simpler models, i.e. Moving Reference Frame technique and three different body-force models, are studied and their results are compared to the ones obtained from the Sliding Mesh approach. The results indicate that one of the body-force models which takes the guide vanes as well as the impeller induced flow swirl into account has the best compromise between the robustness and accuracy among the investigated pump models.
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| 3. |
- Eslamdoost, Arash, 1982, et al.
(författare)
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Application of Control Volume Energy Balance for Analysing Propeller-Hull Interaction in Presence of Free-surface
- 2019
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Ingår i: Sixth International Symposium on Marine Propulsors.
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Konferensbidrag (refereegranskat)abstract
- Reynolds-Transport Theorem can be employed for analysing the conservation of energy equation over a control volume. Through this approach we can decompose the propeller delivered power into mechanical and thermal energy components. This approach not only enables us to qualitatively describe the flow but also makes it possible to quantify different energy flux components and understand the energy loss mechanisms within the studied system. Employing this method, the effect of free-surface on propeller-hull interaction is studied for an axisymmetric body in the vicinity of free-surface relative to a deeply submerged body. The required flow quantities for the control volume analysis are obtained from a Reynolds- Averaged Navier-Stokes approach together with a Volume-of-Fluid method for capturing the free-surface. The mechanical and thermal energy flux components have been computed for control volumes of different sizes, even including the free-surface. These results deviate less than 0.5% from the propeller delivered power which verifies the applicability of the method for further analysis of the interaction effects. The self-propelled hull is studied in two different depths and thus the propeller loadings and efficiencies are different. The analysis of energy flux components quantitatively explains the reasons for the differences.
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| 4. |
- Eslamdoost, Arash, 1982, et al.
(författare)
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Energy Balance Approach for Studying Waterjet-Hull Interaction Effects
- 2023
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Ingår i: Progress in Marine Science and Technology. - 2543-0955. ; 7, s. 275-289
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Konferensbidrag (refereegranskat)abstract
- Waterjet-hull interaction effects are usually studied by analyzing hull attitude in the presence of a waterjet unit as well as the counteracting resistance and thrust forces. Since the waterjet unit is integrated with a hull, net thrust cannot be accurately measured. Instead, it is suggested to use an alternative measurable thrust, gross thrust, to study the interaction effects. Gross thrust is the momentum flux change through the waterjet unit and is calculated by obtaining axial velocity distribution at the inlet to the waterjet unit and the nozzle outlet. However, this approach does not provide detailed information about system power consumption. In this paper, a more comprehensive method is suggested in addition to the momentum flux approach. The method is based on the investigation of energy flux through the waterjet system. This approach not only enables us to qualitatively describe the flow but also makes it possible to quantify different energy flux components and understand the energy loss mechanisms within a waterjet system. The required flow quantities for this analysis are obtained from a Reynolds-Averaged Navier-Stokes approach together with a Volume-of-Fluid method for capturing the free surface. The transport equation for energy is also solved for obtaining the viscous losses in the form of internal energy increase in the flow. The sum of mechanical and thermal energy components computed by analyzing energy flux through the waterjet system deviates less than 0.5% from the pump-delivered power. This confirms the capability of the proposed method for capturing the decomposition of different energy components in the flow. Further analysis of the decomposition of energy flux through the waterjet system is carried out to identify the loss components in the flow.
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| 5. |
- Illini, Oliver, et al.
(författare)
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Mobocertinib in Patients with EGFR Exon 20 Insertion-Positive Non-Small Cell Lung Cancer (MOON): An International Real-World Safety and Efficacy Analysis
- 2024
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Ingår i: International Journal of Molecular Sciences. - : MDPI. - 1661-6596 .- 1422-0067. ; 25:7
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Tidskriftsartikel (refereegranskat)abstract
- EGFR exon 20 (EGFR Ex20) insertion mutations in non-small cell lung cancer (NSCLC) are insensitive to traditional EGFR tyrosine kinase inhibitors (TKIs). Mobocertinib is the only approved TKI specifically designed to target EGFR Ex20. We performed an international, real-world safety and efficacy analysis on patients with EGFR Ex20-positive NSCLC enrolled in a mobocertinib early access program. We explored the mechanisms of resistance by analyzing postprogression biopsies, as well as cross-resistance to amivantamab. Data from 86 patients with a median age of 67 years and a median of two prior lines of treatment were analyzed. Treatment-related adverse events (TRAEs) occurred in 95% of patients. Grade >= 3 TRAEs were reported in 38% of patients and included diarrhea (22%) and rash (8%). In 17% of patients, therapy was permanently discontinued, and two patients died due to TRAEs. Women were seven times more likely to discontinue treatment than men. In the overall cohort, the objective response rate to mobocertinib was 34% (95% CI, 24-45). The response rate in treatment-naive patients was 27% (95% CI, 8-58). The median progression-free and overall survival was 5 months (95% CI, 3.5-6.5) and 12 months (95% CI, 6.8-17.2), respectively. The intracranial response rate was limited (13%), and one-third of disease progression cases involved the brain. Mobocertinib also showed antitumor activity following EGFR Ex20-specific therapy and vice versa. Potential mechanisms of resistance to mobocertinib included amplifications in MET, PIK3CA, and NRAS. Mobocertinib demonstrated meaningful efficacy in a real-world setting but was associated with considerable gastrointestinal and cutaneous toxicity.
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| 6. |
- Khraisat, Qais, 1995, et al.
(författare)
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Model to Full Scale Numerical Considerations in the Context of Cavitation
- 2023
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In recent years, there has been a growing interest in gaining in-depth understanding of ship hydrodynamics at full-scale conditions. Currently, there are only well-established procedures and guidelines for scaled models provided by the ITTC and supported through research findings. Although model testing and simulations give an insight into understanding ship hydrodynamics such as wake, resistance, propeller cavitation, and noise; scale effects create variations relative to actual operating conditions. In geometrically relative terms, it is well known that the boundary layer at full scale is generally thinner than model scale with delayed separation and weaker bilge vortices. Therefore, one can only obtain an accurate understanding of ship hydrodynamics under actual operation by conducting full-scale studies. However, such investigation raises additional considerations and challenges such as surface roughness modeling. The development of robust numerical methods aided by the continuous increase of available computational power has now opened the opportunity to perform such analysis. For this reason, the aim of this research is to showcase numerical considerations for full-scale simulations together with comparisons of model-scale results.
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| 7. |
- Vikström, Marko, et al.
(författare)
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The Effect of Porous Data Surface Shape and Size on Ship Noise Prediction using the FWH Acoustic Analogy with Incompressible Solver for a Cavitating Propeller
- 2022
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Ingår i: Proceedings of the seventh International Symposium on Marine Propulsors - smp'22. - 2414-6129. - 9788269112030 ; , s. 166-173
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Konferensbidrag (refereegranskat)abstract
- Using Ffowcs-Williams and Hawkings (FWH) acoustic analogy with an incompressible solver has become a rather common approach for ship noise prediction. Here the method is studied for a model scale container vessel. The numerical study includes both the ship hull and a rotating propeller, using the sliding mesh approach. The simulations are performed for a condition with cavitation around the tip of the propeller blades to study the propeller induced noise including the contribution from cavitation. To complement this study, e.g., to exclude any wall reflections and rotating sources, an additional pure monopole source case study was performed with both incompressible and compressible methodology. Since cavitation is a volume source acoustic term there is a need to use a Porous Data Surface (PDS) in combination with the FWH acoustic analogy. The choice of PDS shape and size using FWH is studied both for the model scale container vessel as well as for the pure monopole source case. The results show that when using different PDS shapes, a directionality effect is evident when using the incompressible solver. The Sound Pressure Level (SPL) is dependent on the receiver angular location in relation to the PDS. The directionality effect is largest for a PDS shape where there is a large variation in distance from the source to the PDS faces, e.g. box. Furthermore, there is also a receiver distance discrepancy for the incompressible solver with FWH. The SPL curves for different receiver distance do not coincide for higher frequencies. Using a compressible solver and FWH, the shape effect and receiver distance discrepancy is not present.
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