Pulp CFD: Hollywood, the Elephant, and the Acronym

Hollywood has been tantalizing the public and tormenting wind engineers with stunning visual effects and the idea of computational wind tunnels. The reality is the physical atmospheric boundary layer wind tunnel has nearly infinite resolution of fluctuating turbulent properties. The equivalent resolution with current turbulence modeling techniques will require billions and perhaps trillions of cells and computing resources at the limits of our imagination. If the true time varying information obtained from an atmospheric boundary layer wind tunnel is out of our reach within the near future with computational methods, what is within our reach? Qualitative analysis (i.e., design A is better than design B) seems the nearest to reality. Additionally, the indoor environment, (i.e., laboratories, offices, auditoriums) while still of large scale are often driven by mean flow properties with secondary turbulent effects. For the indoor environment CFD is being used (and validated!) to evaluate occupant comfort and safety in the pre-build phase. These modern models of indoor spaces are still requiring millions of cells and mid-scale parallel computing. It is now evident that the questions architects and HVAC engineers are asking of CFD cannot be resolved by single desktop computers. The trend is toward integrated industrial applied CFD comparable to that used by the automotive and defense industry. This operation mode enables the smooth transition of computational models from CAD though solvers to the post-processing and client presentation.