Simulation king Nick Wirth
F1 Racing: Virtual engineering is the common thread in your activities. How did you become so committed to it?
Nick Wirth: For 15 years with Honda, during the post-season review they’d say, “We’ve had a successful year but the competition are going to come back stronger – what are we going to do to ensure that we carry on winning?” And I’d say, “We need to invest more in aerodynamic research. We need to do more CFD." It ended up with us investing in CFD to a level that is far beyond what is used in F1 now.
F1R: In what way?
NW: It’s simply because the rules have been written, in my opinion, in a very unfortunate way, which means that the full power of modern CFD cannot be exploited in F1 because of the regulated restriction in resources in CFD.
F1R: Why is that?
NW: Because doing CFD right is so computationally difficult to do. Doing it right is a very high grid count, compressible flow, full physics, large-eddy simulation. It’s the gold standard of what we know about CFD. The top teams can use it on occasion but they can’t use it every single run because of the F1 CFD rules.
F1R: What you mean by the ‘gold standard’?
NW: The critical phrase is ‘full physics’ – aerodynamic and thermodynamic simultaneous simulation. So, F1 tyres run at about the boiling point of water, brake discs at a peak temperature of 1000ºc and the water coolers inside the engine are running at maybe 120-130ºc. There’s all this heat transfer going on and that’s critical to simulate. Warm air going down the car affects the forces on the back of the car differently to if it was cold, because it’s less dense. It was only when we added all these processes into our models that they started to correlate really well to full-scale. The Honda sportscars we never took to a windtunnel. All those cars we developed in CFD only.
F1R: What are the applications beyond motorsport?
NW: The defence industry is one area. For instance, Lockheed Martin asked us to come up with a concept that would enable a submarine to launch an unmanned aerial vehicle while underwater. We had to design a tube that would transform into a small aircraft in three tenths of a second and only weigh a kilo and a half, so we applied all our motorsport simulation knowledge to making this aircraft as efficient as it could be. Our propellers use 20 per cent less electrical power to generate the same thrust as the best commercial composite propellers.
We’re doing a lot of work in architecture on pedestrian comfort and building loads, and we also helped Apple with the natural ventilation system on their new campus. To work out the flow structures we had to model the whole valley Cupertino is set in!
Something else we can do now, which hasn’t been solvable in simulation before, affects tall buildings. You can use a windtunnel to work out how much a building sways in the wind, but you have no idea if the cladding is going to scream. We can get it so they can see those problems and engineer them out before building and we’re going to present our solution to the world in Chicago on May 30.
F1R: How did you end up re-engineering the fridge?
NW: We’d worked with a number of partners, including Eddie Stobart, on the road haulage side, to re-engineer their trailers to be more aero efficient and they were typically seeing a five per cent improvement.
When talking to Marks and Spencer about their vehicle aerodynamics, they asked us to take a look at their chiller cabinets. They were good at keeping sandwiches cold but were expensive and kept the shops cold. If they put doors on it had a disastrous effect on sales. We built a model, ran a high grid count, compressible flow, full physics, largeeddy simulation – making it the most sophisticated fridge ever built – and that enabled us to understand and invent a means to control the air spill. Our retro-fit solution takes 30 seconds to fit. If every supermarket has one it will reduce the UK’S overall electricity consumption by one per cent...