Mechanical engineering researchers model cerebral aneurysms on CITI supercomputer

Mechanical engineering researchers model cerebral aneurysms on CITI supercomputer

BY JAN ODEGARD
Special to the Rice News

What do you get when you combine the latest techniques in computational fluid mechanics and fluid-structure interactions with Rice’s fastest supercomputer? One of the most detailed depictions of the blood flow in an aneurysm and a potential glimpse at the future of medical diagnostics.

An aneurysm is a weakened area of a blood vessel that bulges outward like an overinflated inner tube. Should an aneurysm burst, the internal bleeding is potentially deadly. Understanding the blood-flow dynamics in aneurysms is critical for doctors to know how these vascular abnormalities begin, grow and rupture as well as how to treat them.

Scientists on Rice’s Team for Advanced Flow Simulation and Modeling (T*AFSM) are tackling this major computational challenge in cardiovascular fluid mechanics. Using the advanced numerical methods and parallel computing algorithms they have developed for modeling fluid-structure interactions, they sought to accurately model the interactions between flowing blood and pulsating arteries.

The challenge stems from the interdependence between blood flow and arterial geometry. The mathematical equations describing each must be solved simultaneously because blood flow depends on arterial geometry and vice versa.

Using Rice’s Cray XD1 supercomputer and the T*AFSM computer methods and programs, team members Bryan Nanna, graduate student in Mechanical Engineering and Materials Science (MEMS); Sunil Sathe, research scientist in MEMS; and Brian Conklin, assistant professor at Baylor College of Medicine and research scientist in MEMS, created computer models of two types of cerebral aneurysms based on the computed tomography scans of two aneurysm patients.

JEFF FITLOW

Using Rice’s Cray XD1 supercomputer, scientists (from left) Sunil Sathe, Bryan Nanna and Tayfun Tezduyar, all members of Rice’s Team for Advanced Flow Simulation and Modeling, were able to model what blood flow in an aneurysm looks like during the heartbeat cycle. Not pictured is team member Brian Conklin.

The computations on the Cray showed what the blood flow in the aneurysms looked like as the heart was pumping blood through the damaged vessel. Using the information, the researchers captured snapshots of the flow patterns during the heartbeat cycle.

“With access to the large-scale computational resources of the Cray, we are able to move our computer-modeling research forward to new and more challenging applications,” said T*AFSM leader Tayfun Tezduyar, the James F. Barbour Professor in Mechanical Engineering. “The Cray XD1 is transforming our research since it permits us to address these new challenges with a level of modeling accuracy previously not feasible.”
Rice’s Cray XD1 was purchased in 2005 with a $2 million grant from the National Science Foundation. It can conduct almost 3 trillion floating-point operations, or teraflops, the standard measure of supercomputer performance, per second.

The Cray is operated by Rice’s Computer and Information Technology Institute, a research-centric institute dedicated to the advancement of applied interdisciplinary research in the areas of computation and information technology.

—Jan Odegard is executive director of Rice’s Computer and Information Technology Institute.