Fantastic Voyage

David Pacchioli
January 28, 2008
Rob Kunz/ARL

CFD model showing molecular bonds formed between a cancer cell and a white blood cell.

Penn State's Applied Research Laboratory has a long, proud history in experimental fluid dynamics, beginning with construction of the Garfield Thomas Water Tunnel in 1949.

In the 1970s, ARL researchers began working with computer simulations of fluid flow as a complement to experimental approaches. Until recently, however, computational fluid dynamics (CFD) was focused almost exclusively on developing undersea systems for the lab's traditional sponsor: the U.S. Navy.

That work continues apace, but as computer power has increased and CFD algorithms have matured, additional research opportunities have emerged, says Rob Kunz, head of ARL's Computational Mechanics Division. One area of recent activity is the biomedical.

Until recently, Kunz explains, the major fluid-flow systems within the human body—respiration and circulation—were just too complicated to model. However, he says, "The dramatic improvements in medical imaging over the last ten years have helped us map complexities of internal geometry, like vasculature and respiratory bronchioles, that we just couldn't get at before." In addition, decades of research have yielded new levels of insight into physiological processes at microscopic and molecular scales, such as gas uptake, nutrient exchange and cellular interactions.

Building on these developments, the Computational Mechanics Division currently has three projects aimed at biomedical applications. In one, with NIH sponsorship, ARL researchers are working with professor of mechanical engineering Dan Haworth and colleagues at Drexel University to model the fluid mechanics of the respiratory system, Kunz says, "ultimately down to the molecular level." The goal is to one day join this model with imaging technology as a new tool for diagnosing respiratory ills.

In a second project, also NIH funded, bioengineering professor Cheng Dong is working with Kunz on modeling the physical processes of cancer-cell transport and interactions in the bloodstream, in order to better understand the process of metastasis.

The third and largest project is the development of a left ventricular assist device (LVAD)—a temporary pump employed to relieve stress on the heart during recovery from heart attack. "Its development involves detailed fluid dynamics modeling, both to optimize hydrodynamic performance and to minimize clotting and hemolysis," Kunz notes. "We're working on a third-generation design now, and the University has patents pending."

In addition to these three active projects, collaborative research between ARL's Fluids and Structural Mechanics Office, the Bioengineering Department, and Hershey Medical Center has advanced several artificial heart and LVAD concepts (and their components) over the past 20 years. CFD has become a critical element in the design, optimization and assessment of these devices.

To Kunz, it's no great leap from undersea technologies to biomedical ones. "The same basic technology that goes into the design of a submarine propeller 15 feet in diameter goes into designing a blood pump that fits in a chamber of your heart," he says. "The physics—the governing equations—are the same."

Robert F. Kunz, Ph.D., is head of the Computational Mechanics Division in the Applied Research Laboratory,

Last Updated January 28, 2008