Originally Posted by
tartare
Given the exponentially increasing speed and power of computers - how far away are we from being able to design and test aircraft entirely as designs inside a digital wind tunnel, and go straight from a digital 3D model to full scale flight ready prototype?
Quite a long way.
CFD simply is not capable today to model the complex flow mechanics which are critical for things like stall characteristics. If I'm honest, wind tunnel models aren't always so great at that either. But the difference is years and years of experience in interpreting the implications of wind tunnel data for the real world. Engineering is an inherently conservative endeavour, especially when put against the kind of scrutiny that certification of an aircraft implies. So it'll be a long time before CFD reaches the same capability as wind tunnel testing, and even longer before its trusted to the same extent.
The state of the art today (with improvements which have occurred in tunnel testing, not just CFD) is that you can often get results faster fom a WT test, even accounting for build times etc., than you can for CFD. Sometimes its eve simpler and cheaper to just flight test something!