# Fishing Vessel Bulbous Bow Hydrodynamics—A Numerical Reverse Design Approach

^{1}

^{2}

^{3}

^{4}

^{5}

^{*}

## Abstract

**:**

## 1. Introduction

## 2. Towing Tank Experiments

#### 2.1. Model Ship Description

#### 2.2. Experimental Set-Up

## 3. CFD Description

#### 3.1. Numerical Equations

#### 3.2. Numerical Domain

#### 3.3. Numerical Boundary Conditions

#### 3.4. Numerical Mesh

## 4. Results

#### 4.1. CFD Validation

#### 4.2. Bows Designs Analysis

## 5. Conclusions

- There is a critical point at Fn = 0.25 from where the resistance grows exponentially due to the high influence of the pressure resistance that is linked with wave resistance.
- For low velocities, the hulls with no bulbous bow in general show good efficiency until Fn 0.25, from where the hulls do not seem to have the correct shape.
- For the different load conditions and speeds after Fn = 0.25, the case of BBM shows higher efficiency. It is clear then that the bulbous bow works better, reducing pressure resistance.
- The viscous resistance grows linearly for all the cases. This resistance becomes more significant in the total resistance for Fn < 0.25, although the BBM does not seem to change the total amount of viscous force that much.
- The pressure resistance is predominant from Fn 0.25 onwards. This resistance is the main source of resistance, which means ship designers should focus on reducing this component of resistance.
- The pressure distribution around the hull demonstrates how it changes with the Fn number, revealing a larger hollow wake as Fn increases.
- The pressure distribution is practically the same for the two cases without a bulbous bow. When compared with a bulbous bow hull, it is noticeable that the hollows in the ship’s shoulders are less pronounced, sometimes resulting in a nearly linear wake generation around the hull.

## Author Contributions

## Funding

## Data Availability Statement

## Acknowledgments

## Conflicts of Interest

## Nomenclature

List of variables: | |

L | Ship total length (m) |

${L}_{WL}$ | Ship waterline length (m) |

B | Ship beam (m) |

T | Ship draught (m) |

∇ | Volumetric displacement of ship (${\mathrm{m}}^{3}$) |

S | Wetted surface area (${\mathrm{m}}^{2}$) |

${C}_{B}$ | Block coefficient |

$\lambda $ | Scale |

${C}_{M}$ | Midship section coefficient |

Fn | Froude number (Fn = V$\sqrt{g{L}_{WL}}$) |

g | gravitational constant (${\mathrm{m}/\mathrm{s}}^{2}$) |

F | Total drag resistance (N) |

FV | Viscous resistance (N) |

FP | Pressure resistance (N) |

${\rho}_{\infty}$ | Water density |

${C}_{P}$ | Pressure coefficient |

${C}_{T}$ | Drag force coefficient coefficient |

$WH$ | Wave height (m) |

## References

- Guldhammer, H.E.; Harvald, S. SHIP RESISTANCE—Effect of Form and Principal Dimensions; Danish Technical Press: Copenhagen, Danmark, 1965. [Google Scholar]
- Holtrop, J. A statistical re-analysis of resistance and propulsion data. Int. Shipbuild. Prog.
**1984**, 31, 272–276. [Google Scholar] - Bilec, M.; Obreja, C.D. Ship resistance and powering prediction of a fishing vessel. IOP Conf. Ser. Mater. Sci. Eng.
**2020**, 916, 012011. [Google Scholar] [CrossRef] - Matínez-López, A.; Díaz Ojeda, H.R.; Míguez González, M.; Marrero, Á. Environmental Inefficiencies of Short Sea Shipping Vessels by Optimization Processes Based on Resistance Prediction Methods. J. Mar. Sci. Eng.
**2022**, 10, 1457. [Google Scholar] [CrossRef] - Larsson, L.; Raven, H.; Paulling, J. Ship Resistance and Flow; Principles of Naval Architecture; Society of Naval Architects and Marine Engineers: Alexandria, VR, USA, 2010. [Google Scholar]
- Ferreiro, L.D. The social history of the bulbous bow. Technol. Cult.
**2011**, 52, 335–359. [Google Scholar] [CrossRef] - Barrass, B. Ship Design and Performance for Masters and Mates; Elsevier: Amsterdam, The Netherlands, 2004. [Google Scholar]
- Díaz-Ojeda, H.; Pérez-Arribas, F.; Turnock, S.R. The influence of dihedral bulbous bows on the resistance of small fishing vessels: A numerical study. Ocean. Eng.
**2023**, 281, 114661. [Google Scholar] [CrossRef] - Pérez-Arribas, F.; Silva-Campillo, A.; Díaz-Ojeda, H.R. Design of Dihedral Bows: A New Type of Developable Added Bulbous Bows—Experimental Results. J. Mar. Sci. Eng.
**2022**, 10, 1691. [Google Scholar] [CrossRef] - Ren, Z.; Wang, J.; Wan, D. Numerical Simulations of Ship Bow and Shoulder Wave Breaking in Different Advancing Speeds. In Proceedings of the International Conference on Offshore Mechanics and Arctic Engineering, Madrid, Spain, 17–22 June 2018; American Society of Mechanical Engineers: New York City, NY, USA, 2018; p. V07AT06A010. [Google Scholar] [CrossRef]
- Chakraborty, S. What’s Importance of Bulbous Bow of Ships. Marine Insight. 21 May 2017. Available online: https://www.marineinsight.com/naval-architecture/why-do-ships-have-bulbous-bow/ (accessed on 1 February 2024).
- Kracht, A. Design of bulbous bows. In Proceedings of the SNAME Annual Meeting, New York, NY, USA, 16–18 November 1978; Volume 86. [Google Scholar]
- Hoyle, J.W.; Cheng, B.H.; Hays, B. A Bulbous Bow Design Methodology for High-Speed Ships; Society of Naval Architects and Marine Engineers-Transactions; Society of Naval Architects and Marine Engineers: Alexandria, VR, USA, 1986; Volume 94. [Google Scholar]
- Hagen, G.E.A. A Guide for Integrating Bow Bulb Selection and Design into the U.S. Navy’s Surface Ship Hull Form Development Process, Naval Sea Systems Command; Technical Note No. 885-55W-TN0001; NAVSEA: Washington, DC, USA, 1983. [Google Scholar]
- Peri, D.; Rossetti, M.; Campana, E.F. Design optimization of ship hulls via CFD techniques. J. Ship Res.
**2001**, 45, 140–149. [Google Scholar] [CrossRef] - Sharma, R.; Sha, O.P. Practical hydrodynamic design of bulbous bows for ships. Nav. Eng. J.
**2005**, 117, 57–76. [Google Scholar] [CrossRef] - Watle, A. Flexible Bulbous Bow Design-A Hydrodynamic Study. Master’s Thesis, NTNU, Trondheim, Norway, 2017. [Google Scholar]
- Bertolotti, M.; Verazay, G.; Pagani, A.; Errazti, E.; Buono, J. Flota pesquera Argentina. Evolucion 1960–1998 con una actualizacion al 2000. In El Mar Argentino y Sus Recursos Pesqueros. Evolución de la Flota Pesquera, Artes de Pesca y Dispositivos Selectivos; INIDEP: Mar del Plata, Argentina, 2001. [Google Scholar]
- Oyuela, S.; Sosa, R.; Otero, A.D.; Arribas, F.P.; Diaz-Ojeda, H.R. An experimental and numerical hydrodynamic study on the Argentinian fishing vessels. IOP Conf. Ser. Mater. Sci. Eng.
**2023**, 1288, 012047. [Google Scholar] [CrossRef] - Arribas, F.P.; Oyuela, S.; Otero, A.D.; Sosa, R.; Diaz-Ojeda, H.R. The use of Ctrl+Z in ship design: Removing a bulbous bow. IOP Conf. Ser. Mater. Sci. Eng.
**2023**, 1288, 012044. [Google Scholar] [CrossRef] - Specialist Committee: Procedures for Resistance, Propulsion and Propeller Open Water Tests of 23rd ITTC 2002. ITTC—Recommended Procedures and Guidelines: Model Manufacture, Ship Models; ITTC: Nairobi, Kenya, 2002. [Google Scholar]
- 28th ITTC Quality Systems Group. ITTC—General Guidelines for Uncertainty Analisys in Resistance Tests; ITTC: Nairobi, Kenya, 2017. [Google Scholar]

**Figure 9.**Wave pattern for different Fn and draught = LC heavy. Left: CFD. Right: EFD. First row: Fn = 0.26, second row: Fn = 0.37, third row: Fn = 0.45.

Main Particulars | Symbol | Unit | Full Scale LC Light | Model LC Light | Model LC Medium | Model LC Heavy |
---|---|---|---|---|---|---|

Model scale | $\lambda $ | [-] | - | 20 | 20 | 20 |

Length on waterline | ${L}_{WL}$ | [m] | 32.68 | 1.634 | 1.662 | 1.641 |

Length, overall submerged | ${L}_{OS}$ | [m] | 34.795 | 1.670 | 1.740 | 1.740 |

Breadth | B | [m] | 9.28 | 0.464 | 0.464 | 0.464 |

Draught | T | [m] | 3.30 | 0.165 | 0.180 | 0.195 |

Displacement volume | ∇ | [${\mathrm{m}}^{3}$] | 599.40 | 0.075 | 0.085 | 0.095 |

Wetted surface area | S | [${\mathrm{m}}^{2}$] | 392.67 | 0.982 | 1.058 | 1.124 |

Block Coefficient | ${\mathrm{C}}_{B}$ | [m] | 0.60 | 0.60 | 0.61 | 0.64 |

Midship section coefficient | ${\mathrm{C}}_{M}$ | [m] | 0.86 | 0.86 | 0.87 | 0.89 |

**Table 2.**Combination of uncertainty in measurement for resistance at Fn = 0.14, Fn = 0.26, Fn = 0.37, and Fn = 0.45. Repeat test N = 4.

Uncertainty Components | Fn = 0.14 | Fn = 0.26 | Fn = 0.37 | Fn = 0.45 |
---|---|---|---|---|

Hull geometry | 0.05 | 0.05 | 0.05 | 0.05 |

Speed | 0.067 | 0.067 | 0.067 | 0.067 |

Water temp. | 0.03 | 0.03 | 0.03 | 0.03 |

Dynamometer | 4.73 | 1.04 | 0.35 | 0.12 |

Repeat test, Deviation ^{a} | 5.00 | 3.50 | 1.50 | 1.10 |

Combined for single test | 6.88 | 3.65 | 1.54 | 1.11 |

Repeat test, Deviation of mean | 2.50 | 1.75 | 0.75 | 0.55 |

Combined for repeat mean | 5.35 | 2.04 | 0.83 | 0.57 |

Expanded for repeat mean | 10.70 | 4.08 | 1.66 | 1.14 |

^{a}Repeat test, Deviation = (Repeat test, Deviation of mean) × ${\mathrm{N}}^{1/2}$.

Patch | U | p | k | $\mathit{\omega}$ | $\mathit{\mu}$ Turbulent |
---|---|---|---|---|---|

Inlet | uniform | fixed flux | fixed value | fixed value | fixed value |

Outlet | zero gradient | zero gradient | zero gradient | zero gradient | zero gradient |

Atmosphere | zero gradient | zero gradient | zero gradient | zero gradient | zero gradient |

Bottom | symmetry | symmetry | symmetry | symmetry | symmetry |

Midpl/Side | symmetry | symmetry | symmetry | symmetry | symmetry |

Ship | no slip | fixed flux | wall function | wall function | wall function |

Case | Mesh Cells | Fn | F [N] | Error (%) |
---|---|---|---|---|

EFD | - | 0.45 | 40.27 | - |

Mesh 1 | 633.938 | 0.45 | 40.26 | 0.02 |

Mesh 2 | 903.744 | 0.45 | 41.76 | 3.70 |

Mesh 3 | 1.213.419 | 0.45 | 40.34 | 0.17 |

Mesh 4 | 2.485166 | 0.45 | 41.16 | 2.21 |

Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content. |

© 2024 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).

## Share and Cite

**MDPI and ACS Style**

Díaz Ojeda, H.R.; Oyuela, S.; Sosa, R.; Otero, A.D.; Pérez Arribas, F.
Fishing Vessel Bulbous Bow Hydrodynamics—A Numerical Reverse Design Approach. *J. Mar. Sci. Eng.* **2024**, *12*, 436.
https://doi.org/10.3390/jmse12030436

**AMA Style**

Díaz Ojeda HR, Oyuela S, Sosa R, Otero AD, Pérez Arribas F.
Fishing Vessel Bulbous Bow Hydrodynamics—A Numerical Reverse Design Approach. *Journal of Marine Science and Engineering*. 2024; 12(3):436.
https://doi.org/10.3390/jmse12030436

**Chicago/Turabian Style**

Díaz Ojeda, Héctor Rubén, Sebastian Oyuela, Roberto Sosa, Alejandro Daniel Otero, and Francisco Pérez Arribas.
2024. "Fishing Vessel Bulbous Bow Hydrodynamics—A Numerical Reverse Design Approach" *Journal of Marine Science and Engineering* 12, no. 3: 436.
https://doi.org/10.3390/jmse12030436