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Building ships in the clouds
Improving vessel design with Simcenter Cloud HPC
Most industries are under growing pressure to reduce their environmental impact and shipping is no exception.
From 2023, the International Maritime Organization (IMO) requires all vessels over 400 gross tons to undergo measurement of the energy efficiency design index (EEXI). This helps to identify ways to improve fuel efficiency – the less fuel used, the fewer harmful emissions are generated.
But calculating and improving EEXI is far from straightforward. It requires detailed analysis of a ship’s hydrodynamics and propulsion systems, which takes up considerable time and resources.
DNV Maritime Advisory provides technological expertise to shipbuilders and shipowners to help them meet this challenge and many more. And simulation is key to solving these problems in the most efficient way.
Real-time simulation
Cosmin Ciortan, principal specialist at DNV Maritime Advisory, says there has been a big push towards EEXI compliance recently. “CFD simulation is the only way that this can be addressed, especially for existing vessels where towing tank models or test data are not available,” he explains.
They are also involved in many projects that require aerodynamic analysis of ship superstructures with a high level of geometrical complexity.
Ciortan and his team use Simcenter STAR-CCM+ for much of their simulation work due its multiphysics capabilities. “We never find ourselves limited by the physics and complexity that we can model,” he says. “One of the things we like most about the software is the ability to see what is happening with a simulation in real time. If something is wrong with the setup, it becomes much easier to find.”
Saving time and money
Over their lifetime at sea, ships are subject to changing environmental conditions that can affect their performance. DMV Maritime Advisory are often brought in to troubleshoot issues that have come up or evaluate modifications designed to improve performance.
This is where simulation comes into its own as it’s much cheaper and faster than testing with physical models. And it allows for full scale virtual models using more realistic wave and wind conditions than could be created in a test environment.
Ciortan references one particular issue that came to his team: “We were contacted by a ship owner who had found that, under certain conditions, exhaust gases were being drawn into HVAC intakes. This is a serious safety concern and time was of the essence to understand the problem and find a solution.”
But taking a commercial vessel out of service to undergo engineering work is incredibly expensive and disruptive. To minimize this downtime, Ciortan’s team reproduced the scenario in Simcenter STAR-CCM+ and confirmed they were seeing the same problems as the real ship. They then worked through several ideas that could remedy the issue with the least amount of engineering work and that could be done without having to take the vessel to a shipyard. They identified a potential solution that involved extending the height of the pipework inside the funnel and then had to work out how to get all the necessary materials in place without shipyard facilities and cranes.
They worked through several options with the customer, running simulations that covered the problematic range of conditions, including different wind speeds, directions, and engine load conditions with associated exhaust discharge rates.
Powered by the cloud
All these calculations took a significant amount of computing power and needed to be completed as quickly as possible – faster than the existing on-premise resources that DNV Maritime Advisory had. So they made use of Simcenter Cloud HPC, a turnkey solution for running CFD simulations on the Amazon Web Services (AWS) cloud, direct from inside Simcenter STAR-CCM+. This allowed them to run more simultaneous simulations than they could previously, meaning they could reach the ideal solution within the short timeframe demanded. “I don’t think we could have turned the project around as quickly as we did without Simcenter Cloud HPC,” says Ciortan. “And it really delivered – we had a solution and a happy customer at the end.”
“The other great thing is it allows us to scale our resources up or down as needed,” Ciortan goes on. “Our simulation workload is often unpredictable. There will be times where we have an extremely heavy simulation to run and we need more resources fast. As Simcenter Cloud HPC runs on preconfigured hardware it’s quick and easy to use. The simulations start immediately so we know when we will get results and we don’t need to worry about how it works in the background.”
It's simply not cost-effective for organizations such as DNV Maritime Advisory to keep all the resources and licenses needed for the biggest projects on-premise. There would be too much time when they’re not being fully utilized which would increase the cost of all their smaller projects. So, by having their own HPC cluster for most work, and then scaling up when necessary with Simcenter Cloud HPC, they can deliver projects in the most efficient way, keeping costs down for customers.
And for smaller companies working in simulation there is no longer a need to invest in their own HPC cluster. It will often be cheaper to run everything on Simcenter Cloud HPC, making it much easier for new companies to get started and grow without having to find significant funds to invest in hardware.
