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 w as studied. Expressions for fluid dynamic torque given by Jeffery (192 3) were used in the Euler equations of motion to determine fiber orien tation. Fiber orientation was found to depend on two nondimensional pa rameters; its aspect ratio and a nondimensional parameter related to t he fluid viscosity, flow velocity gradient, and fiber mass density and diameter. Fiber orientation was calculated for different fiber diamet ers and was compared with that obtained by Jeffery (1923) for normal b reathing in humans and rats. The inertial effects are significant when fiber diameter exceeds 1 mu m.