Flying without wingsSep 2018 Neil Cumins; INGENIA online ISSUE 76"Later this year, HMS Queen Elizabeth, the first of the UK’s new Queen Elizabeth Class aircraft carriers, will head out to the US to operate with the F-35B aircraft for the first time. In a small corner of Lancashire, a group of pilots has been ‘flying’ the aircraft in a flight simulator in preparation. Neil Cumins spoke to Dr Steve Hodge, BAE Systems’ Senior Simulation Engineer, about how the £2 million simulator provides a realistic and immersive experience....
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RECREATING AIR FORCEA hugely significant – and world-leading – advance was made in terms of integrating air-wake modelling into the F-35B flight simulator. “If you imagine the air flowing over the sea,” Dr Hodge explains, “it starts to create vortices and turbulence whenever it hits the ship. The angle the wind hits the ship at creates different patterns of airflow over the deck and around the ship. The pilot has to fly through the turbulent air wake behind the carrier in order to land on it, so it’s been really important to model that ship air wake in order to make the simulator as realistic as possible.” Sponsored PhD students at the University of Liverpool have been looking at advanced computational techniques to model the air wake, before integrating their findings into the simulation using high-performance computers: “The machine we use for that needs a lot of processors and memory to hold all the air-wake data, before mapping it onto a grid to apply it to the aircraft as it flies through the air wake. We’ve got a machine with one terabyte of data and 64 processors to model the air wake in real time.”
This sort of processing has taken the team into unchartered territory, according to Dr Hodge. “Elements have been done in the US, but there hasn’t been a place where it’s been done on this scale – and there hasn’t been a situation where everything’s been brought together. You might have someone who’s done air-wake modelling, and there are plenty of aircraft flight simulators out there, but there’s no other simulator in the world where you can fly the F-35 to the aircraft carrier, stand inside the FLYCO simulator and see it land while interacting with the pilot. This is the only place where the air wake and ship motion are modelled and the simulator accurately reflects the aircraft handling qualities and the airflow around the ship. There’s nowhere else all these models have been put together and integrated into one place in such high fidelity.”
WIND BREAKERSThe computational analysis required to accomplish this in an engineering simulator is also innovative. “We can basically scale up the wind models to represent different wind strengths,” Dr Hodge says, “but when it comes to different wind directions, you don’t have any choice but to compute the air wake. As the wind goes up in magnitude, the flow pattern doesn’t really change a great deal apart from the vectors getting scaled up slightly because of the wind speed. However, as you change the direction that the wind hits the island of the ship, then the patterns of flow over the deck change dramatically, so we needed to do the computations for each wind direction. We’ve got a database of wind directions going all round the ship. Each one takes about two or three weeks to process on a high-performance computing cluster, and then we extract the data in real time. The computation is quite an important process; it’s not just calculating one solution, but multiple time steps. We end up with 30 or 40 seconds of flow data we can replay in the simulator.”
To confirm the air-wake model was delivering accurate results, Dr Hodge and his team validated it in a water tunnel at the University of Liverpool using a 3D-printed 1:200 scale model of the aircraft carrier. The team used water instead of air to create a ‘wet’ wind tunnel, which allowed it to submerge the model of the carrier in a tank and then blow water over it. The team then used anemometers to measure the air speed over the ship at different points. This was still an aerodynamic test rather than a hydrodynamic one, substituting air for water, and comparing the results with anemometer surveys of the newly-constructed HMS Queen Elizabeth....
...Such has been the complexity of Dr Hodge’s work that he has used it as the basis of a company-funded PhD. In 2010, his work on ship/air integration using simulation saw him graduate with a doctorate, reflecting the challenges of accurately modelling both the aircraft and its carrier.
He concludes by acknowledging the remarkable advances in computing power that have made the current F-35/QEC simulator possible: “If someone had shown me this simulator when I first started modelling the aircraft carrier 18 years ago. I would have been astounded. It’s amazing what we can do now compared to what we could achieve in those days, and it’s just getting better all the time with computing power, digital projectors and other advances. It makes you wonder what we’ll be able to accomplish in 20 years’ time.”
Regardless of how technology evolves in the coming years, the research conducted for the aircraft carriers and F-35B will contribute to future knowledge of air-wake modelling, across other platforms and simulators.
BIOGRAPHYDr Steve Hodge is Senior Simulation Engineer at BAE Systems. He has worked in the company’s simulation department for 20 years, having previously worked on the Hawk and Harrier fighter aircraft."
Graphic: "A visualisation of vortices being shed from the superstructure as wind flows around the aircraft carrier, modelled using computational fluid dynamics. This is an example of the air-wake models being integrated into the F-35/QEC integration simulator © University of Liverpool" [looks like throwing spaghetti at a wall to see wot sticks]
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Source: https://www.ingenia.org.uk/Ingenia/Arti ... 1f3bddfd7c 
25 Oct 2018, 10:06
Tell the weasel he's dreamin'. Big show of support? That happens already. "Bout time others showed support and I'm not including parts or all of any country to denigrate. 
