THE EFFECT OF FIBER INERTIA ON ITS ORIENTATION IN A SHEAR-FLOW WITH APPLICATION TO LUNG DOSIMETRY

The effect of fiber inertia on its orientation in a flow fiber field was studied. Expressions for fluid dynamic torque given by Jeffery (1923) were used in the Euler equations of motion to determine fiber orientation. Fiber orientation was found to depend on two nondimensional parameters; its aspect ratio and a nondimensional parameter related to the fluid viscosity, flow velocity gradient, and fiber mass density and diameter. Fiber orientation was calculated for different fiber diameters and was compared with that obtained by Jeffery (1923) for normal breathing in humans and rats. The inertial effects are significant when fiber diameter exceeds 1 mu m.