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How to Run 100 Ship Design Configurations in Less than 10 min with Extrality Deep Learning Physics

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Antoine Reverberi
December 22, 2022
5mn
Antoine is a former naval architect at Damen with experience in ship design and optimization. He joined Extrality as a CFD engineer and brings his expertise in fluid dynamics to several projects with customers.
If you are a naval architect, you probably know how long the ship design process takes. In this article, you will learn how Extrality can help you perform resistance calculations much earlier on while relying on your existing simulation tools, thus reducing the risk of project deviations and opening up more opportunities to evaluate new designs.

Ship design process

Ship design is an iterative process. Each iteration attempts to obtain a balanced ship design that satisfies specific needs and requirements. The design and construction of a service vessel most often takes more than one year and the process can be divided into several stages:

1. Concept design: definition of the ship's basic characteristics (ship type, deadweight, propulsion and service speed).

2. Preliminary design: creation of technical material for tender and contract, estimation of design and material cost, determination of main dimensions.

3. Contract design: detail calculation to ensure ship performance, refinement of the general arrangement (GA), basic design of the hull and systems arrangements.

4. Detail design: creation of detailed material for hull production, support to the assembly.

The most well known representation of the ship design process is the design spiral of Evans (Evans, 1959). While the design spiral converges to the center new design phases are gone through. If one activity takes longer than planned, a whole iteration will be delayed as well. Additionally, another iteration has to be done if a mistake is made, also causing a delay.

Figure: The design spiral of Evans emphasizes that many design issues interact and must be considered in sequence, in increased detail at each pass around the spiral, until a single design that satisfies all constraints and balances all considerations is reached.

Integrate simulation into design

Historically, the marine industry heavily relied on statistical approaches and regression analyses. With the emergence of advanced tools, there has been a significant effort to integrate simulation into the ship design process. According to Harries (Harries, 2008) we are going from modeling design towards simulation-driven design. It means that we drive the final solution not from the modeling, but out of the calculations or simulations.

Figure: Simulation-driven design is putting simulation at the front of the design process and using simulation technology to create a design instead of using simulation to analyze it later. Courtesy of https://www.istockphoto.com.

From simulation to real-time prediction

Within each phase, resistance calculations play an important role as they provide insight into how efficient a ship’s design is. Unfortunately, as these types of simulations often require a lot of computation time and effort, they typically get shifted further down the spiral. This is especially true in the case of Computational Fluid Dynamics (CFD).

Let’s demonstrate with a Multi-Purpose Ship (MPS) used to carry a huge variety of bulk cargo. The vessel operates in a big window, so a large number of speeds and drafts need to be considered in order to obtain the full resistance profile. For example, if we want to evaluate speeds of 9 to 21 knots (2 knots increments) and loading drafts of between 4.25 and 8.25 m (1.0 m increments), 105 data points (7 speeds, 5 draughts and 3 design variations) need to be generated. If you had to set up and run each one of these with CFD, it would involve a significant amount of engineering time and most likely cut into your productivity.

This is why Extrality developed a Deep Learning Physics platform that allows you to investigate a full range of configurations and operation points with minimal manual effort. The platform can predict fluid behavior to assess the performance of new hull designs in a few minutes, thus saving some valuable time in the early stages of a design project. It is accessible directly from the web, without any installation needed. All simulations can be run in 3 clicks!

Figure: 1) Upload the geometry, 2) Run the full range of configurations and operation points with a single click and 3) Download the post-processing: volume, surface, evolution curves, coefficients.

Conclusion

Using Extrality to run all 105 simulations takes just 10 minutes to complete the entire set… saving engineers time for value-added tasks: explore a range of solutions and innovate. And ship owners will also receive their slices of the pie if a vessel’s efficiency can be improved in a shorter time span with Extrality. For more information about hull form optimization with Extrality, check out this article.

Bibliography

Evans, 1959. Basic Design Concepts. In: Journal of the American Society for Naval Engineers, Volume 71, pp. 671-678.

Harries, 2008. Serious Play in Ship Design. In: Tradition and Future of ship design in Berlin.