The science of sound has a special importance in the marine world. Acoustic waves travel faster and further in water than in air, which has made sonar a vital technique for navigation as well as for locating subsea objects and structures. But the efficiency of sound propagation in water presents a problem for ships and submarines that want to avoid detection, which means that the key goal for many of the acoustic specialists at QinetiQ – the global defence and security company headquartered in the UK –  is to make these maritime platforms as quiet as possible.

“It’s a hiding game,” says Dave Steele, who is technical lead for a team that designs and develops acoustic materials that stifle the sound reflected back from ships, submarines and other water-based structures. “Sound bounces off any object in the water, and so for anything that wants to remain hidden we need to control that energy.”

Acoustic specialists at QinetiQ are investigating various different methods to suppress the noise generated by maritime platforms. In Toby Hill’s team, for example, the aim is to design propulsion systems that enable ships and submarines to move through the water as silently as possible. “The huge power plants and propellers in these propulsion systems generate lots of energy that is dumped into the sea,” Hill explains. “Our aim is to minimize the amount of noise they produce by developing shapes that interact more efficiently with the water flow.”

Research and innovation

Across most of these activities the key customer for QinetiQ is the UK’s Ministry of Defence (MoD), which in April 2023 renewed a long-term contract, called the Maritime Strategic Capability Agreement (MSCA), that commits almost £260m to research and innovation at QinetiQ over the next 10 years. While the renewal of the MSCA will sustain key skills and facilities across several of QinetiQ’s sites in the UK – with the ultimate aim of maintaining the MoD’s ability to design, build and operate the Royal Navy’s surface and subsurface fleet – it also provides its technical teams with the springboard they need to plan for the future.

“We now have a commercial baseline that allows us to start exploring longer term solutions,” comments Steele. “It’s an exciting time, because we will be able to strengthen our core capabilities while also leveraging our skills and expertise to explore new opportunities with a range of different customers.”

That long-term view is driving a need for a new influx of acoustic scientists and engineers. “We need more people because we have lots of work, and we need to strengthen our capability,” says Hill. “The MSCA is a long-running contract, but customers from the MoD or the commercial sector also come to us with specific problems that need to be solved within a shorter timeframe.”

Whether developing noise-cancelling materials or reducing the sound made by propulsion systems, acoustic physicists like Hill and Steele typically exploit a combination of numerical, analytical and experimental techniques to take their solutions from initial idea to full integration and test. “For each project we might identify some candidate materials based on our prior knowledge and experience, and then we use analytical techniques and finite-element modelling to optimize the performance of the material for the specific application,” explains Steele. “We then create small-scale samples to assess their behaviour against our numerical predictions, and if that checks out we progressively scale up our testing regime towards the full-scale solution.”

The scientists and engineers at QinetiQ have access to some unique experimental facilities to gather the real-world data they need to be confident in their designs. For Hill and his team, that means measuring the noise, vibration and turbulence created by both model structures and full-scale solutions in large water tunnels and other hydromechanical testing facilities. “It takes at least five years and billions of pounds to build these maritime platforms,” he says. “Our customers need to make multimillion-pound design decisions, and it makes sense for them to invest in the experimental facilities needed to prove that the design will perform as expected.”

Field trials are also vital to verify the performance of design solutions in the harsh underwater environment, with submarines in particular subject to large variations in temperature and pressure. The technical teams work closely with their customers to translate lab results and numerical data into realistic exercises that address the specific challenges of each application. “We have the capabilities to test the performance of the materials when they are applied to end platform,” explains Steele. “We need to prove the design in a real-life scenario to de-risk the technology solution for the customer.”

Peppered in with these long-term strategic projects are more urgent operational requests that demand expert acoustics knowledge. Team members are also often involved in collaborative projects, both within QinetiQ and with external companies who may be developing and deploying integrated platforms. “The unusual combination of skills and experience within the team puts us in a unique position to solve a diverse range of problems.” says Steele. “Customers often come to us because they recognize that we have this amazing core knowledge across a broad range of materials.”

Training provided

However, both Steele and Hill recognize that new recruits are unlikely to offer such a specialized combination of knowledge and skills from the outset – particularly when the classified nature of the work generally restricts the roles to UK nationals. “We don’t expect anyone to have experience of what we do,” says Hill. “We provide the training needed for new members of the team to develop the specific skills needed to work in maritime acoustics.”

A small number of people, like Hill, join QinetiQ with relevant experience from industry or academia, but in most cases new recruits are younger scientists and engineers who are just starting out on their careers. “Generally we’re looking for graduates, PhDs or post-docs who are interested in an area that’s relevant for us and might have developed some transferable skills,” says Hill. “People from the physics community are likely to have the numerical or experimental skills we are looking for, and might be interested in solving the sort of problems we work on.”

New graduates have the option of joining QinetiQ’s two-year training scheme, in which they are based in a “home” business while taking a series of six-month placements in other areas, or building their skills and expertise within a specific technical area. Steele’s team has also hosted undergraduate students who spend a year in industry as part of their degree, which in some cases has led to a permanent position. “Placement students and new graduates get involved in project work right from the start,” he says. “We give them context, training and support, but we also throw them into the work and provide them with the opportunity to do some real science.”

Strong focus on collaboration

Once in the organization, QinetiQ’s scientists and engineers have plenty of opportunities to develop their skills and experience, whether they decide to stay in the same team or move to another part of the business. Either way, the diverse range of projects and strong focus on collaboration provides sufficient variety and scientific challenge to keep things interesting. “Everyone works on several projects at the same time, which means that no two days are the same,” says Steele. “It’s not just a conveyer belt of designing new materials – we get to identify a problem, investigate it, come up with a solution, and then think about how the solution might be used in another setting.”

The acoustic scientists and engineers within QinetiQ are also well aware that their specialist knowledge and skills is providing a tangible benefit, whether for an external customer or the UK’s national security. “We act as a consultancy, using our expertise to work in partnership with our customers to devise and optimize a solution,” says Steele. “People who join us from academia appreciate the context and purpose for their work, knowing that it yields an outcome that is genuinely useful for our customers.”

Combined with the diverse opportunities within QinetiQ, Steele says that technical specialists within the organization generally enjoy a long and varied career. “QinetiQ is blessed with an intelligent, engaged and motivated workforce, which makes it a brilliant place to work,” says Steele. “People tend to stay for the variety and challenge of the science, and for the other people they get to work with.”

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