>> Continued
However, the costs were not as high as initially thought and
there are other benefits accruing. Hackland commented, "We now know
that it was about a third of the capital costs up front for
building the facility and we are running at about 24% cheaper than
the wind tunnel.
We expected it to cost the same but in actual fact we are seeing
a significant savings. One of the reasons is that we put the
building underground which keeps the temperature fairly constant
and the APC equipment is proving to be very efficient."
Renault's wind tunnel uses accurate, one-third scale models for
tests but the time taken to create and modify these models causes
delays. Using a supercomputer simulation allows 3D digital models
to be constructed from the computer-aided design software within
seconds with a massive saving on time.
Wind tunnel
"With the wind tunnel you're making a model and that takes
time," said Hackland. "It's just one model. So you put the model on
the test rig but you're constantly having to stop while you modify
that model. Whereas, for the CFD guys, it is possible to work in
parallel with the job currently running.
While this happens, the team is creating new jobs, putting them
into the queue and that makes them much more productive. We run
about 20 tests at a time so it's a lot more physical capacity than
one wind tunnel."
The models are created using 3D printing techniques. Every part
of the car is prototyped in this way from computer-aided design
(CAD) software. The printer uses a liquid gel that solidifies when
a thin laser beam hits it.
The printer spreads a thin layer of the gel across a flat
surface plate and the laser, guided by the CAD design draws shapes
for that particular layer of the model.
Then another layer is added and lasered and so the process
repeats until the model is completed. Extremely intricate and
accurate shapes can be formed but the process is slow.
Restrictions
In comparison, the supercomputer can take the same drawings and
create a model of the car in far less time and this is a particular
advantage if a major change is required.
That's not the end of it all. As Hackland pointed out, "You can
do other things, too. You can simulate two cars behind one another
or you can simulate cornering.
There's so much more you can do with CFD. Some parts of the car
still lend themselves better to the wind tunnel but there are parts
of the car that are only done in the CFD - they don't even do it in
the wind tunnel anymore.
"Simulation has become the big thing because they're reducing
the amount of time that we can run a car around the track. We used
to have an open season and you could do what you liked so every
second week we were testing something.
Now we've got 50 days a year, and there's possibly more
restrictions coming next year, so you really have to rely on
simulation to be accurate because if you get to the track and it
doesn't do what it said in the simulation you're in trouble."
Hackland's work will be put to the test in early hours of Sunday
morning when the team competes in the Austrailian Formula 1 Grand
Prix.