Bulbous Bow Shape Optimization (original) (raw)

Surrogate-Based Optimization Using an Open-Source Framework: The Bulbous Bow Shape Optimization Case

Mathematical and Computational Applications

Shape optimization is a very time-consuming and expensive task, especially if experimental tests need to be performed. To overcome the challenges of geometry optimization, the industry is increasingly relying on numerical simulations. These kinds of problems typically involve the interaction of three main applications: a solid modeler, a multi-physics solver, and an optimizer. In this manuscript, we present a shape optimization work-flow entirely based on open-source tools; it is fault tolerant and software agnostic, allows for asynchronous simulations, and has a high degree of automation. To demonstrate the usability and flexibility of the proposed methodology, we tested it in a practical case related to the naval industry, where we aimed at optimizing the shape of a bulbous bow in order to minimize the hydrodynamic resistance. As design variables, we considered the protrusion and immersion of the bulbous bow, and we used surrogate-based optimization. From the results presented, a ...

Hydrodynamic study of the influence of bulbous bow design for an Offshore Patrol Vessel using Computational Fluid Dynamics

Ciencia y tecnología de buques, 2018

The resistance of a ship is of vital importance in giving greater viability to the development of a design project, since at lower ship resistance, the power demand to achieve a desired design speed will be lower which will reduce the amount of power to be installed in the ship resulting in lower fuel consumption. The use of computational fluid dynamics to analyze and optimize hull form and its appendages permits the hydrodynamic performance of the ship to be improved from the early design stages, allowing improvements to the hull shape and appendages. This paper shows a qualitative analysis which was performed to reduce the resistance of the OPVMKII (Second Generation Offshore Patrol Vessel) in its preliminary design stage by means of designing and integrating three types of bulbous bow with the ship´s hull and analyzing the resistance curves obtained using computational fluid dynamics.

On the Effect of Forebody Optimisation of Fishing Vessels

In a recent study, forebody optimisation of a fishing vessel was treated to show the usefulness of a modest but practical combination of a computational hull resistance/flow analysis and optimisation technique. The techniques were based on the Dawson's algorithm and quadratic programming supported by thin-ship theory and were able to develop optimal hull forms for lower wave resistance as well as to predict the order of merits correctly. Towing tank measurements accompanied the computational work to test the predictability of the computational analysis and optimisation techniques. The findings implied that severe resistance penalties were generated from the vessel's shoulders and bluff bow, common on today's fishing boats. In consultation with the designer and operator a new refined forebody and bulbous bow was proposed for an existing vessel. A 1/30 th scale model was constructed and tested, the resistance tests indicated a dramatic performance improvement. Encouraged b...

Drag Based Shape Optimization of Submarines and AUVs Using CFD Analysis

Progress in Marine Science and Technology

Nowadays, underwater vehicles have a wide range of applications both in military, scientific, commercial and security fields. Next to Submarines, Autonomous Underwater Vehicles (AUVs) are increasingly spreading thanks to their capabilities to carry out a significant variety of missions, including interacting with underwater infrastructures, coastal and underwater inspections, intelligence gathering, environmental and fish monitoring and, of course, research and fight against underwater threats. One of the main performance characteristics of an underwater vehicle is its resistance curve. The estimation of this curve is a crucial factor in preliminary design phases in order to correctly choose and dimension the right propulsion plant and propeller and, in general, to reach operational requirements. In the last decade, with the advent of higher computing power and robust algorithms, the application of Computational Fluid Dynamics (CFD) analysis is rapidly emerging as a fast, reliable a...