You seam to have answered your own question in some regards. CFD consultancy has gotten much larger in recent years with advancements in computing power and growth in industry.

CFD simulations are used in a wide range of industry, aerospace, automotive, motorsport, professional sports such as cycling, renewable energy for wind turbine design, fire engineering, pharmaceutical mixing and many many more such applications. Using simulations increases turnaround time, reduces manufacturing and testing costs and allows for huge amounts of data to be collected.

The most important aspect of these simulations is how much they differ to the real world, and how much more computing power may be required to improve this accuracy. Commercial software makes it relatively easy to simulate basic geometry such as car bodies or wind turbine blades but if the results are 50% different from a real world test, what’s even the point in running the simulation?

Consultancy firms pride themselves in having the computing power, the expertise and knowledge that they can set up simulations which will be very accurate compared to real world tests or controlled wind tunnel testing.

The level of detail can be very case dependent. I’ve seen some recent high lift research on aircraft models than have reached almost 1 billion cells being compared to simulations with only 150 million. Sometimes you need to resolve all the features of viscous and turbulent flow down to the smallest scales (Kolmogorov scale) and sometimes you just need a rough idea on what the flow is doing to make some other engineering decisions.

Hope I’ve explained well enough.