Estimation and prediction of effective inflow velocity to propeller in waves

Ueno, Michio; Tsukada, Yoshiaki; Tanizawa, Katsuji

doi:10.1007/s00773-013-0211-8

Cited by 29 publications

(19 citation statements)

References 2 publications

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“…The variation of spatially averaged wake in waves can be divided into two factors: a) Mean change in wake due to pitching motion of ship, as explained by Faltinsen, Minsaas et al [23] and b) Wake fluctuation due to induced particle velocities caused by incoming waves and surge motion of ship, as discussed by Ueno, Tsukada et al [24]. Both these factors are caused by potential effects.…”

Section: Computation Of Wake In Wavesmentioning

confidence: 99%

Effect of waves on cavitation and pressure pulses

Taskar

Steen

Bensow

et al. 2016

Applied Ocean Research

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In view of environmental concerns, there is increasing demand to optimize the ships for the actual operating condition rather than for calm water. Now, in order to apply this for propeller design, a first step would be to study the effects of waves on propeller operation. Therefore, the aim of this paper is to identify and quantify the effect of various factors affecting the propeller in waves. The performance of KVLCC2 propeller in the presence of three different waves has been compared with calm water performance. Changes in performance in terms of cavitation, pressure pulses, and efficiency have been studied. Significant increase in pressure pulses has been observed due to wake change in waves even though cavitation did not show any significant change. An analysis using cavitation bucket diagram in different wave conditions indicates that a propeller optimized for calm water wake may perform much worse in presence of waves. Therefore, having wake variation at least in critical wave conditions (where the wavelength is close to ship length) in addition to calm water wake could be very useful to ensure that the propeller performs equally well in presence of waves.

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Section: Computation Of Wake In Wavesmentioning

confidence: 99%

Effect of waves on cavitation and pressure pulses

Taskar

Steen

Bensow

et al. 2016

Applied Ocean Research

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“…Hence, in presence of waves, mean wake changes along with the fluctuations. Ueno, Tsukada et al (2013) have demonstrated that fluctuating wake velocities are caused by the wave induced particle motion and surge motion of the ship. Therefore, they state that wake velocities can be calculated as follows-…”

Section: Procedures To Estimate Propeller Inflow Velocitymentioning

confidence: 99%

“…Nakamura and Naito (1975) have demonstrated the effect of waves and ship motions on thrust deduction and wake fraction of a ship. Wake is also affected by pitching motion of a ship, causing increase in average wake (Faltinsen, Minsaas et al 1980) along with wake fluctuations (Ueno, Tsukada et al 2013). Significant changes in wake field were observed in presence of waves and ship motions in the RANS simulations carried out by Guo, Steen et al (2012), where the nominal wake field was obtained in waves.…”

Section: Figure 1 the Effects Of Waves On Ship Propulsionmentioning

confidence: 99%

“…The coefficient is different from 1.0 in case of head and bow-quartering waves since the waves reaching the propeller are modified due to the presence of the hull in front of it (Ueno, Tsukada et al 2013). However, in case of following and stern quartering waves this coefficient is not required as the waves are directly felt by the propeller without significant disturbance from the hull.…”

Section: Procedures To Estimate Propeller Inflow Velocitymentioning

confidence: 99%

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The effect of waves on engine-propeller dynamics and propulsion performance of ships

et al. 2016

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This paper investigates the effect of waves on the propulsion system of a ship. In order to study the propulsion in different wave conditions, a procedure for wake estimation in waves has been implemented. A clear drop in the propulsion performance was observed in waves when engine propeller dynamics, wake variation and thrust and torque losses were taken into account. This can explain the drop in vessel performance often experienced in presence of waves in addition to the effect of added resistance. Therefore, performance prediction of ships in rough weather can be improved if the effects of waves on the propulsion system are considered. Specific problems causing drop in performance have also been identified. System response in case of extreme events like propeller emergence has been simulated for analyzing the performance and safety of the propulsion system. The framework of enginepropeller coupling demonstrated in this paper can also be used to analyze different components of propulsion system (e.g. propeller shaft, control system) in higher detail with realistic inputs. This paper is a step towards optimizing the propulsion of ships for realistic operating conditions rather than calm water condition for energy efficient and economic ships.

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“…However, shortcomings in the setup did result in unsatisfactory results, and the topic was not taken up further. Other publications on the continuous development of such a setup by the National Maritime Research Institute of Japan can also be found [7], [8], [9], [10]. Based on the foregoing, inclusion of a model scale hull in a HIL setup seems an attractive extension and important enrichment of the currently available toolset to simulate, analyse, and improve dynamic performance of integrated systems at sea.…”

Section: Introductionmentioning

confidence: 99%

Potential of Hardware-in-the-Loop simulation in the Towing Tank

Vrijdag

2016

OCEANS 2016 MTS/IEEE Monterey

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Abstract-Traditionally, model scale tests of ships are carried out without taking into account the dynamics of the shipboard systems that are involved in the operation under consideration. An example of this is the way that model scale free sailing tests in waves are carried out. The ship model is mounted with an electric motor, shaft and propeller and subsequently tests are carried out with constant propeller speed. In some cases constant shaft torque or constant power are employed. However, neither of these options reflects realistic behaviour of the drive system, because in waves and during manoeuvres the propeller speed, torque and power are in fact variable and their dynamic behaviour is governed by the drive train characteristics. The question arises to what extent, and in which cases, the dynamics of the shipboard systems affect the overall system behaviour. In this paper the application of Hardware-in-the-Loop (HIL) simulation in a ship model basin or towing tank is explored as a means to answering that question. The ambition is to develop an instrumented model scale ship of which the components of the drive train and its control are included by means of a correctly scaled time domain computer simulation model of the propulsion system. This simulation model is to run on a real-time processor which, via IO cards, provides electric power to an electric motor on-board the instrumented model scale ship, which in turn drives one or multiple shafts and propulsors. In this paper the role of scale effects on the test set-up is discussed. It is also shown that, in order to simulate realistic drive train dynamics in waves and during manoeuvres, it must be ensured that the combination of partial simulated drive train on the one hand and electric motor dynamics plus shaft and propeller inertia on the other hand should, as a total, represent the real dynamics of the drive train system.

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Estimation and prediction of effective inflow velocity to propeller in waves

Cited by 29 publications

References 2 publications

Effect of waves on cavitation and pressure pulses

Effect of waves on cavitation and pressure pulses

The effect of waves on engine-propeller dynamics and propulsion performance of ships

Potential of Hardware-in-the-Loop simulation in the Towing Tank

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