After 40 Years Why Hasn't the Computer Replaced the Wind Tunnel?

The debate between wind tunnels and computers to develop aeronautical systems has persisted for over 40 years. On the one hand, the majority of wind tunnels used today in aeronautical research, development, test, and evaluation were designed and commissioned in the 1950s and 60s. These facilities remain the backbone of the aeronautical development process, although they are becoming more challenging to maintain. On the other hand, rapid advances in computer hardware and software offer the potential to dramatically alter the design and development process for flight systems through the application of computational science and engineering. However, after 40 years of promises to eliminate the need for test facilities, advanced computational science and engineering have still not diminished significantly the need for test facilities or reduced the overall cycle time for development of flight systems. As many wind tunnel test hours are used today to develop a flight system as were used 20 years ago.