School of Chemical Engineering and Materials Science

SCHOOL OF CHEMICAL, BIOLOGICAL & MATERIALS ENGINEERING

and

THE UNIVERSITY OF OKLAHOMA BIOENGINEERING CENTER

The University of Oklahoma

Norman, Oklahoma

2004 – 2005 Seminar Series

CBMECBMECBMECBMECBMECBMECBMECBMECBMECBMECBMECBMECBMECBMECBMECBMECBMECBMECBMECBMECBMECBMECBMECBMECBMECBMECBMECBMECBMECBMECBMECBMECBMECBMECBMECBMECBMECBMECBMECBMECBMECBMECBMECBME

DR. CONSTANTINE POZRIKIDIS

PROFESSOR

MECHANICAL AND AEROSPACE ENGINEERING

WHITAKER INSTITUTE OF BIOMEDICAL ENGINEERING

UNIVERSITY OF CALIFORNIA, SAN DIEGO

LA JOLLA, CALIFORNIA

Will present a seminar on

“MODELING AND NUMERICAL SIMULATION OF THE

FLOW-INDUCED DEFORMATION OF RED BLOOD CELLS”

Red blood cells are liquid capsules containing a viscous fluid that is enclosed by a biological membrane which consists of a lipid bilayer and a supporting network of proteins. In the absence of flow, the cells assume the equilibrium shape of a biconcave disk. When subjected to flow, the cells deform in a way that depends on the type and strength of the flow and the mechanical properties of the membrane. In this presentation, an integrated mathematical framework for the equations governing the interior and exterior fluid dynamics and the membrane mechanics is discussed under the auspices of low-Reynolds-number hydrodynamics and nonlinear theory of thin shells. The governing equations are solved using a novel implementation of the boundary element method in global Cartesian coordinates, which accounts for the membrane incompressibility, elasticity, and bending stiffness. Numerical simulations are carried out to investigate the deformation of a cell in simple shear flow and tube flow, in the physiological range of physical properties and flow conditions. The cells are found to perform flipping motion accompanied by periodic deformation in which the cross-section of the membrane in the plane of the flow alternates between the nearly biconcave resting shape and a reverse S shape. The period of the overall rotation is in good agreement with experimental observations of red blood cells suspended in plasma. The numerical results illustrate in quantitative terms the distribution of the membrane tensions developing due to the flow-induced deformation, and reveal that the membrane is subjected to stretching and compression in the course of the rotation. The success of these simulations motivates the further development of computational techniques, with the long-term goal of simulating particulate blood flow under a broad range of conditions.

THURSDAY, OCTOBER 28, 2004

COOKIES AND COFFEE -- 3:15 P.M.

SEMINAR -- 3:30 P.M.

SARKEYS ENERGY CENTER, ROOM M-204

THIS IS A REQUIRED SEMINAR FOR CHE 5971