Pre- and post-swirl fins design for improved propulsive performances

Gaggero, Stefano; Martinelli, Mattia

doi:10.1080/09377255.2021.1934362

Cited by 3 publications

(6 citation statements)

References 19 publications

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“…Any SBDO design method requires a parametric description of the geometry by which it automatically handles each variation towards the (Pareto) convergence on the basis of the KPI of the previous designs. In the case of the ESDs under investigation, the parametric description is rather simple and takes inspiration from similar previous design activities [18,32]. Pre-swirl ducts are the most complex geometries under consideration, and the parameters for the PSFs and the WEDs designs are derived from their parametric description (Figure 7).…”

Section: Parametric Description Of Esdsmentioning

confidence: 99%

“…The use of flapped and "controllable" fins in front of the propeller was proposed to cope with non-constant operative conditions (slow steaming, fouling, weather, change in draft) and to ensure the highest possible energy saving, which reached a shaft power reduction of 4% in the case of a bulk carrier [17] tested in the framework of the Blue INNOShip Initiative supported by the Danish government (http://www.blaainno.dk, accessed on 10 March 2023). In the case of high-speed ships, however, solutions such as post-swirl fins [18,19] were preferred, with the aim of reducing the total drag of the ship by realizing a cost-free thrust thanks to the accelerated slipstream of the propeller. Energy savings, in these cases, were limited to 2%, but at the cost of very simple modifications to the hull.…”

Section: Introductionmentioning

confidence: 99%

“…In this respect, the current study addresses the design of pre-swirl fins (PSFs), preswirl ducts (PSDs) and wake-equalizing ducts (WEDs) for the reduction in the delivered power of the vessel by using the design method and criteria developed in [18,32]. The SBDO is realized thanks to a combination of RANSE and BEM analyses, respectively, for the prediction of the hull resistance and flow (RANSE) and the characterization of the unsteady propeller functioning in the effective wake altered by the presence of the ESD (BEM).…”

Section: Introductionmentioning

confidence: 99%

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Pre-Swirl Ducts, Pre-Swirl Fins and Wake-Equalizing Ducts for the DTC Hull: Design and Scale Effects

Nicorelli,

Villa,

Gaggero

2023

JMSE

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A pre-swirl fin (PSF), pre-swirl duct (PSD) and wake-equalizing duct (WED) energy-saving devices (ESD) are designed for the Duisburg Test Case (DTC). To this aim, a simulation-based design optimization method, combining RANSE analyses (ship resistance) with BEM calculations (unsteady propeller performances) in a simplified optimization process realized through a parametric description of ESD geometries, was employed. Fully resolved RANSE analyses were used to validate the outcomes of this affordable design process, which identifies devices capable of saving energy in the delivered power for this type of challenging test case by up to 2.6%. Comparisons with model-scale calculations, furthermore, permit us to discuss the influence of each appendage in different flowfields (model- and full-scale, as well as under the action of the simplified or the resolved propeller) and the reliability of the full-scale extrapolation methods recently proposed for these types of devices.

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Section: Parametric Description Of Esdsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Pre-Swirl Ducts, Pre-Swirl Fins and Wake-Equalizing Ducts for the DTC Hull: Design and Scale Effects

Nicorelli,

Villa,

Gaggero

2023

JMSE

Self Cite

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“…Wang and Lutsey [3], as well as Molland et al [4], have described several methods to increase the efficiency of energy use on ships. These methods include weather routing [5], [6], speed reduction [7], [6], propeller [8], [9], and hull optimization [10], [11], bow modification [12], [13], [14], hull cleaning management or preventing biofouling [15], [16], [17], [18], [19], [20], trimming strategy [21], adding devices [22], [23], [24], [25], [26], using more advanced antifouling [27], [28], [29], and analyzing the coating roughness [30], [31], [32], [33], [34], etc.…”

Section: Introductionmentioning

confidence: 99%

Investigating the Comparison of Ship Resistance Components Between U and v-Shaped Hulls

et al. 2023

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The selection of a hull design with minimal drag is an important effort to reduce emission levels on ships. Two different hull shapes, U and V hulls, have unique properties that affect their drag production, which has been studied extensively in the past. This study aims to re-examine the differences between the two hull types by conducting a simple analysis of drag prediction results using empirical and numerical slender body methods. Both hull models in this study have the same size and volume. The results indicate that the U hull has a higher frictional resistance ( ) than the V hull due to its wider wetted surface area ( ). Additionally, the viscous pressure resistance ( ) and form factor coefficient ( ) of the U hull are also higher than those of the V hull. However, for Froude numbers (Fr) above 0.245, the U hull has lower wave resistance ( ) than the V hull, whereas for Fr below 0.245, the U hull has higher . Overall, the U hull produces a higher total resistance ( ) than the V hull at low speeds, but a lower at high speeds. Therefore, the choice of hull shape for minimizing a ship's resistance is influenced by the desired speed of service. If Fr is low, below 0.24, a V-shaped hull is more suitable. However, if Fr is higher than 0.24, a U-shaped hull is more appropriate.

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“…These emissions reduction measures are a major focus in the fight against climate change and global warming [2,3], as HSMVs pose a particular challenge. On-board methods to decrease emissions [4,5] include optimizing the hull shape [6][7][8][9], utilizing weather routing [10,11], preventing hull roughness caused biofouling [12][13][14][15][16][17][18][19][20][21] or coating [22][23][24][25][26][27], exploring more eco-friendly fuels [28][29][30][31][32], optimizing propellers [33,34], using advanced coating [35][36][37][38][39][40][41] and using the energy saving devices [42][43][44][45]. Efforts to improve energy efficiency in high-speed marine vehicles must also be considered.…”

Section: Introductionmentioning

confidence: 99%

Analysis of the double steps position effect on planing hull performances

Trimulyono,

Hakim,

Ardhan

et al. 2023

Brodogradnja

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Along with developing high-speed craft technology, the planing hull is growing with modifications for better performance. One such technology is stepped hull, both single and double. Planing hull with steps allows the boat to run at a relatively low drag-lift ratio with lower frictional resistance due to reduced wetted area. In this study, the hull was modified with variations in the position of the double steps, which aimed to determine the effect of the first and second step positions on the total resistance, dynamic trim, and dynamic sinkage generated by computational fluid dynamics (CFD). Based on the analysis results, variations in the position of the stepped can change the hull performance. Shortening the distance between the two steps and moving both rearwards toward the transom can lower the total resistance. The dynamic trim and dynamic sinkage decreased as the position of the two steps was shifted further forward. An equation created in a non-dimensional form relates the positions of two steps to the desired results of total resistance, dynamic trim, and dynamic sinkage, namely: {(x1-x2)/L + (x1x2)/(LB)} × Fr∇, where x1 is distance the first step from transom, x2 is the distance of the second step, L is the length of the boat, B is the beam of the boat, and Fr∇ is the volume Froude number.

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Pre- and post-swirl fins design for improved propulsive performances

Cited by 3 publications

References 19 publications

Pre-Swirl Ducts, Pre-Swirl Fins and Wake-Equalizing Ducts for the DTC Hull: Design and Scale Effects

Pre-Swirl Ducts, Pre-Swirl Fins and Wake-Equalizing Ducts for the DTC Hull: Design and Scale Effects

Investigating the Comparison of Ship Resistance Components Between U and v-Shaped Hulls

Analysis of the double steps position effect on planing hull performances

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