Enhancement of asymptotic formula for added resistance of ships in short waves

Yang, Kiwoung; Kim, Yonghwan; Jung, Yoo-Won

doi:10.1016/j.oceaneng.2017.11.010

Cited by 23 publications

(3 citation statements)

References 8 publications

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“…However, the added resistance due to short waves estimated in this way is less accurate because of difficulties in considering the nonlinearity of the diffracted head waves. Therefore, the short-wave correction formula (SNU formula) proposed by Yang et al [16,17] was used to improve the accuracy, and the applied coordinate system is shown in Figure 3. The original asymptotic formula [8] was enhanced in three aspects in the SNU formula.…”

Section: Evaluation Of Total Resistancementioning

confidence: 99%

“…There have also been studies to estimate the added resistance more accurately, focusing on the short wavelength region. Faltinsen et al [8] introduced the asymptotic formula for short waves, and recently, the enhanced asymptotic formula suggested by Yang et al [16,17] provided more reliable results even for relatively fast and slender ships by modifying the original formula from three aspects: finite draught, local steady velocity, and shape above the still-water-level (SWL).…”

Section: Introductionmentioning

confidence: 99%

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Study on Hull Optimization Process Considering Operational Efficiency in Waves

Kim

Lee

et al. 2021

Processes

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This study investigates the optimization of the hull form of a tanker, considering the operational efficiency in waves, in accordance with the recent Energy Efficiency Design Index regulation. For this purpose, the total resistance and speed loss of the ship under representative sea conditions were minimized simultaneously. The total resistance was divided into three components: calm water resistance, added resistance due to wind, and to waves. The first two components were calculated using regression formulas, and the last component was estimated using the strip theory, far-field method, and the short-wave correction formula. Next, prismatic coefficient, waterline length, waterplane area, and flare angle were selected as design variables from the perspective of operational efficiency. The hull form was described as a combination of cross-sectional curves. A combination of the method shifting these sections in the longitudinal direction and the Free-Form Deformation method was used to deform the hull. As a result of applying the non-dominated sorting genetic algorithm to a tanker, the hull was deformed thinner and longer, and it was determined that the total resistance and speed loss were reduced by 3.58 and 10.2%, respectively. In particular, the added resistance due to waves decreased significantly compared to the calm water resistance, which implies that the present tendency differs from conventional ship design that optimizes only the calm water resistance.

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Section: Evaluation Of Total Resistancementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Study on Hull Optimization Process Considering Operational Efficiency in Waves

Kim

Lee

et al. 2021

Processes

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“…The additional term, added to take into account the viscous component of the added resistance, is in a form of an exponential function depending on the block coefficient, ratio of wavelength to ship length, and constants determined by the least squares method based on the available results from the literature. Yang et al [11] have improved the Faltinsen asymptotic formula for calculating the added resistance in short waves. The authors took into account the ship draft, the alteration in the flow velocity around the hull, and the shape of the hull above the waterline.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the Effect of Container Ship Characteristics on Added Resistance in Waves

Martić

Degiuli

Farkas

et al. 2020

JMSE

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Added resistance in waves is one of the main causes of an increase in required power when a ship operates in actual service conditions. The assessment of added resistance in waves is important from both an economic and environmental point of view, owing to increasingly stringent rules set by the International Maritime Organization (IMO) with the aim to reduce CO2 emission by ships. For that reason, it is desirable to evaluate the added resistance in waves already in the preliminary ship design stage both in regular and irregular waves. Ships are traditionally designed and optimized with respect to calm water conditions. Within this research, the effect of prismatic coefficient, longitudinal position of the centre of buoyancy, trim, pitch radius of gyration, and ship speed on added resistance is investigated for the KCS (Kriso Container Ship) container ship in regular head waves and for different sea states. The calculations are performed using the 3D panel method based on Kelvin type Green function. The results for short waves are corrected to adequately take into account the diffraction component. The obtained results provide an insight into the effect of variation of ship characteristics on added resistance in waves.

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