CFD based vortex generator design and full-scale testing for wake non-uniformity reduction

Saydam, Ahmet Ziya; Gokcay, Serhan; İnsel, Mustafa

doi:10.1016/j.oceaneng.2018.01.097

Cited by 13 publications

(8 citation statements)

References 3 publications

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“…In particular, the authors found the present study particularly beneficial when considering key flows for the design of propellers and energy saving devices for full-scale application since it avoids uncertainties from empirical scaling of model scale data and minimises the iterations required to find the optimal ship design. Such a thorough hydrodynamic analysis could avoid the commonly used practice of trial and error that is typically used by some energy saving device designers (Saydam et al, 2018).…”

Section: Discussionmentioning

confidence: 99%

Detailed analysis of the flow within the boundary layer and wake of a full-scale ship

2020

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This article presents a detailed numerical flow assessment of the boundary layer and wake of a full-scale cargo ship. The assessment was conducted using a sophisticated numerical approach that is able to resolve large turbulent scale vortices contained in the flow. The physical flow features of the boundary layer and wake investigated include mean-velocity, near-wall shear stress and vorticity fields. Also, the evolution of the wake from the thick boundary layer over the stern is displayed and analysed in the highest possible detail. Additionally, the detailed information extracted from the boundary layer and wake was the primary input to assess the overall hydrodynamic efficiency of the full-scale general cargo ship. The analysis method followed during this work has been a determinant factor for fast and efficient design of energy saving devices, propellers or rudders that work within the limits of the boundary layer of a ship. In particular, this thorough analysis avoided the necessity to use the commonly used practice of trial and error that is typically followed in the maritime industry.

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Section: Discussionmentioning

confidence: 99%

Detailed analysis of the flow within the boundary layer and wake of a full-scale ship

2020

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“…Passive control devices require no additional energy to operate, whereas, active control devices require additional energy such as electric or magnetic energy to operate. Additionally, the propeller-induced vibrations may be realised after the completion of a ship, and the initiatives that can be taken to suppress the vibration is very limited after this point [25]. Saydam [25] also added that wake modification devices, namely duct, and vortex generator, can be used as retrofit solutions to suppress the vibration.…”

Section: Vibration Isolator Types and Theoretical Analysismentioning

confidence: 99%

“…Additionally, the propeller-induced vibrations may be realised after the completion of a ship, and the initiatives that can be taken to suppress the vibration is very limited after this point [25]. Saydam [25] also added that wake modification devices, namely duct, and vortex generator, can be used as retrofit solutions to suppress the vibration. This section will focus on the discussion of these mechanisms.…”

Section: Vibration Isolator Types and Theoretical Analysismentioning

confidence: 99%

A Review of the Dynamic Analysis of Axial Vibrations in Marine Propulsion Shafting System Due to Propeller Excitation

Amirudin

Kamarumtham

Haripriyono

et al. 2022

AEJ

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Over the past decades, the attenuation of axial vibration due to propeller excitation has long been a complex problem due to the coupling dynamics of the propeller-shafting system. As axial vibration is often the cause of fatigue damage to the propulsion shaft components as well as the root cause to acoustical radiation along a hull of a ship, there has been continuous interest in understanding the complex dynamic characteristics of the coupled propeller-shaft system and the methods to suppress the axial vibration in the system. Therefore, several studies have been conducted to solve this vibration problem on the longitudinal axis of the marine propulsion shafting system. This paper aims to provide the theoretical foundations of this problem by reviewing the modelling techniques of this coupled dynamic problem and cover the vibration reduction strategies that are proposed by the cited studies.

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“…Moreover, the improvement of the hub vortex cavitation resulting from the fins was observed in the numerical calculation. Saydam et al (2018) conducted a parametric modeling study of a vortex generator. The results showed that a reasonably designed vortex generator can significantly improve the inhomogeneity of the wake, thereby reducing the hull vibration.…”

Section: Introductionmentioning

confidence: 99%

Simulation strategy of the full-scale ship resistance and propulsion performance

Guo

Sun

Wang

et al. 2021

Engineering Applications of Computational Fluid Mechanics

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The ship powering performance can be predicted based on model tests or simulations. However, differences exist between the full-scale ship performance and extrapolated model data. Therefore, research on full-scale ship performance simulation has important scientific significance and engineering value. This study used the REGAL general cargo vessel to perform full-scale ship resistance and self-propulsion simulations for various grid numbers, time step sizes, and wall Y+ values and compared the calculation and empirical results. The resistance components, waveform, Courant-Friedrichs Lewy (CFL) number, pressure field, and wake flow field of various resistance simulation conditions were analysed. The wall Y+ value was observed to affect the capture of boundary layer flow, ship pressure field evolution, and waveform, which subsequently affect the ship resistance. A Y+ value within 200 was considered to be appropriate when simulating the powering performance of a full-scale ship. The waveform evolution was significantly affected by the time step size, which should meet the requirement that the CFL number on the free surface is less than 1. When simulating the self-propulsion of a full-scale ship based on sliding mesh, the CFL number on the interface should also be less than 1. Additionally, to obtain the correct propeller excitation force, it was recommended that the time step size be maintained below 1°/step (0.000076 L PP /v).

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CFD based vortex generator design and full-scale testing for wake non-uniformity reduction

Cited by 13 publications

References 3 publications

Detailed analysis of the flow within the boundary layer and wake of a full-scale ship

Detailed analysis of the flow within the boundary layer and wake of a full-scale ship

A Review of the Dynamic Analysis of Axial Vibrations in Marine Propulsion Shafting System Due to Propeller Excitation

Simulation strategy of the full-scale ship resistance and propulsion performance

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