The cone's design has similarities with traditional Arabic wind towers. Image courtesy Adrian Smith + Gordon Gill Architecture

In addition to providing structural support for the roof, the staggered cones bring daylight deep inside the 1.5-million-square-foot complex. More important, they cool the interiors by drawing warm air up and out of the building through their tips. Computational fluid dynamics (CFD), which utilizes numerical methods to simulate the interaction of fluids and gases within complex systems, was employed extensively on this project to ensure that the flow of air through these cones produces the greatest cooling effect.

"We looked to traditional Middle Eastern wind towers when designing the cones," Forest recalls. "At first, we were going on an intuitive reaction that they would work in terms of light and ventilation." To validate their assumptions, the team used FloVENT, a program that predicts 3D airflow, heat transfer, and contamination distribution in and around buildings. ESD did a simple model of the cones, including the courtyards created at their base, to get an initial understanding of conditions. "By doing such a model, we were able to pinpoint areas of air intake and airflow into the base of the cone," explains ESD's Mehdi Jalayerian. "For example, we analyzed the effects of repositioning the intake from the base of the cone to the side. We found that by putting it to the side, air swirls around in the cone and provides more uniform ventilation." CFD analysis was especially useful given the speed at which the project had to be developed. Follow-up testing was performed in wind-tunnel facilities, wait times for which can run up to a month.

In order to ensure that the natural ventilation system functions as planned, CFD software was used to model the building geometry and surrounding wind patterns. Hot winds traveling at high velocities around and over the cone openings create low pressure areas, inducing airflow out of the cones. The cone's shape captures cool air moving in the opposite direction. Image courtesy Adrian Smith + Gordon Gill Architecture

 

Lines in the sand

For The King Abdulaziz Center for Knowledge and Culture in Saudi Arabia, the engineers at Buro Happold are using CFD to study airflow patterns for an entirely different reason. Designed by Snøhetta and expected to open in 2011, the Center will stand atop the oil-rich Dammam Dome as one of the only buildings within the surrounding desert. Commissioned by Saudi Aramco, the world's largest oil company, Snøhetta's design calls for five distinct, rock-like structures to house an auditorium, theater, exhibition hall, museum, and archive.

The King Abdulaziz Center for Knowledge and Culture resembles a rock mass in the desert (top). Streamlines generated using Ansys CFX trace the path and speed of particles moving across and around the building. Different colors refer to varying velocity levels, which are greatest at the building's corners. The white areas represent wells where wind shadows would likely form (below). Images courtesy Buro Happold

An early design envisions a polished facade (above). Image courtesy MIR Visuals

 

Early schemes featured a slick facade meant to evoke the dark, viscous qualities of oil. But unlike structures within urban settings or hilly, wooded areas, the exposed surfaces of this building are subject to destructive winds tossing sand and small stones. "The site is driving this specific set of analyses," explains Matthew Herman, of Buro Happold's Computational Simulation & Analysis group. "CFD has been focused primarily on the particulate matter that's picked up from the surrounding terrain."