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Prediction of Barehull Resistance Curve of a Day-cruise Ship in the Cloud
Meet the Team
- End-User – Costas Carabelas Technical Office (CCTO), ship design office, Athens, Greece
- Team Expert – Vassilios Zagkas, SimFWD Engineering Services, Athens, Greece
- Software Provider – Aji Purwanto, Business Development Director, NUMECA International S.A.
- Resource Provider – Richard Metzler, Software Engineer, CPU 24/7 GmbH
- Technology Experts – Hilal Zitouni Korkut and Fethican Coskuner, UberCloud Inc.
SimFWD is a research, development and application company, providing engineering services in the transport and construction industries. The company focuses on computer aided engineering technologies such as CFD and FEM applied to Ship Design. SimFWD can provide turnkey solutions to complicated generic problems in a cost effective manner, eliminating the overheads normally associated with a dedicated engineering analysis group or department. SimFWD aims at helping customers develop product designs and processes by supplying them with customized engineering analysis and software solutions. www.simfwd.com.
Costas Carabelas Technical Office (CCTO) is a ship design office based in Athens, Greece. CCTO is actively involved in numerous projects in the marine and offshore sector.
Use Case
Objective 1 of this case study was to calculate the calm water resistance of a new small range Cruise Ship concept hull (~90m overall length). The hull-form was developed by CCTO and was specifically designed to combine high capacity and good cruising speed between multiple destinations. Listed below are the main dimensions:
- L.O.A.: 87.00 m
- Breadth: 14.40 m
- Service Speed: 17.00 kn
- Draught: 3.900 m
- Block Coefficient (T=3.90): 0.57
Objective 2 was for the end-user CCTO to get familiarized with the use of FINE™/Marine in an UberCloud application software container and compare the cost-benefit in comparison to resources currently in use. The benchmark was analyzed on the bare-metal cloud solution offered by CPU 24/7 and UberCloud. All simulations were run using version 4.1 of NUMECA’s FINE™/Marine software.
SimFWD provided support to CCTO in setting up the FINE™/Marine model and simulation parameters, having as a goal the generation of an initial Power Curve in a short time. This shall be a good helping point at this design stage and shall be later enhanced by Self-Propulsion tests in FINE™/Marine and verified by model tests.
Challenges and Benefits
The case study was completed without facing any difficulties whatsoever. The entire process right from the access to files in the UberCloud container, running the jobs in the CPU 24/7 Cloud, up to the retrieval of results to a local workstation was very convenient and without any delays. The user-friendliness of the interface was a major advantage!
Simulation Process and Results
Computations on the hull-form were performed for 5 different speeds – 13kts, 15kts, 17kts, 19kts, and 20kts. All computations were performed using a fluid domain consisting of approximately 1 million cells except for a speed of 19kts, where a finer mesh containing approximately 2 million cells was additionally computed. Shown below are results for a speed of 19kts:
Figure. 1 Travelling shot at 19knots: Wetted Surface 676 m²
Parameters | Speeds |
19.0 kts |
|
FINE™/Marine global, Resistance |
Units |
|
Rt (Fx) |
[N] |
417902 |
Trim (Ry1) |
[deg] |
-0.2300 |
Sink (Tz) |
[m] |
3.7600 |
ΔSink (Tz) |
[m] |
-0.1400 |
Figure. 2 Wave Elevation along hull length X.
Figure. 3 Streamlines colored by the relative velocity.
Hull Pressure Effects
The bow hull pressure has a normal distribution over the most affected regions, bow front and stem near the waterline entrance.
Figure 4 Overall Hull Pressure
Figure. 5 Flow Streamlines on the hull
Following are some details regarding the simulation setup:
Number of time steps: 1500
Number of non-linear iterations: 5
Different number of CPUs (10, 16 & 32) were tested on the computation variants. This proved that FINE™/Marine is efficient from the scalability point of view.
Conclusion
The range of computations converged well for all speeds and the overall result was deemed as reliable prediction for the range of bare hull resistance also compared to empirical results and similar designs. This allows CCTO to set the boundaries on their Initial Design process and work towards the next steps with confidence. Results have also given valuable insight on available margin to optimize wave resistance at the bow and streamlines in the after part.
- We showed that the CPU 24/7 HPC bare-metal cloud solution provides performance advantages for NUMECA FINE™/Marine users who want to obtain higher throughput or analyze larger, more complex models.
- FINE™/Marine provides proven highly dedicated tool for naval architects especially with its C-Wizard, embedded automated full-hex OMNIS™/Hexpress mesh generator, easiness-to-use, performance and accuracy reducing the engineering and development time and cost.
- CPU 24/7 and UberCloud effectively eliminate the need to maintain in-house HPC expertise.
- The container approach provides immediate access to high performance clusters and application software without software or hardware setup delays.
- The browser-based user interface is simple, robust, and responsive.
Appendix: UberCloud Application Containers for NUMECA FINE™/Marine
UberCloud Containers are ready-to-execute packages of software. These packages are designed to deliver the tools that an engineer needs to complete his task in hand. In this experiment, the FINE™/Marine software has been pre-installed, configured, and tested, and were running on bare metal, without loss of performance. The software was ready to execute literally in an instant with no need to install software, deal with complex OS commands, or configure.
The UberCloud Container technology allows wide variety and selection for the engineers because the containers are portable from server to server, Cloud to Cloud. The Cloud operators or IT departments no longer need to limit the variety, since they no longer have to install, tune and maintain the underlying software. They can rely on the UberCloud Containers to cut through this complexity.
This technology also provides hardware abstraction, where the container is not tightly coupled with the server (the container and the software inside isn’t installed on the server in the traditional sense). Abstraction between the hardware and software stacks provides the ease of use and agility that bare metal environments lack.