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Unformatted text preview: EAS 4101, S11 University of Florida 1/19/11 1/7 Section 3, Decomposition of Fluid Motion 3 Decomposition of Fluid Motion 3.1 Fluid Kinematics Describes fluid motion without reference to forces. There are four distinct components: o Translational rate o Solid-body-like rotation rate o Dilatation (extensional strain rate) o Shear strain rate Note: because we are dealing with fluids rather than solids, we are interested in strain rates as opposed to strains. EAS 4101, S11 University of Florida 1/19/11 2/7 Section 3, Decomposition of Fluid Motion We can now consider the deformation of the following fluid element from a time t to a time dt We can see that all four motions are shown in the snap shot figure above. o Translation - B to B’ o Rotation - diagonal BD counterclockwise to B’D’ o Extensional Strain (Dilatation) – element appears larger at dt o Shear Strain – square element has deformed and become rhombic 3.1.1 Translational rate In 2-D, the translational rate is the velocity: ˆ ˆ v V ui j 3.1.2 Rotational rate The rotation is defined as the average increase of an angle between two initially perpendicular lines....
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- Spring '08
- Shear Stress, Trigraph, Fluid Motion