An experimental investigation of fiber motion near solid boundaries in simple shear flow
- Univ. of Delaware, Newark, DE (United States). Dept. of Mechanical Engineering
Understanding the motion of fibers in a suspension plays a crucial role in many engineering applications. For instance, the design of successful manufacturing processes for fiber-filled suspensions depends on the ability to account for the interrelation between the structure of the fluid (local fiber orientation, concentration, etc.) and the macroscopically observable rheological and mechanical properties. When a fiber is located a finite distance from a solid wall, the boundary can have significant effects on the fiber`s motion. Fiber-wall interactions are the focus of this investigation. Experiments were conducted using a planar shear flow apparatus. Jeffrey`s equations governing particle motion ere verified in the absence of wall effects. As various aspect ratio fibers were placed closer to the wall Jeffrey`s equations became invalid since they were not formulated to take wall effects into consideration. qualitative observations show that a fiber, with an initial orientation of ninety degrees to the flow direction and an initial location of less than a fiber length from the wall, experiences an increased rate of rotation and adopts a final orientation parallel to the wall. Preliminary analysis suggests scaling the shear rate to account for these effects. The apparent shear rate is a function of the fiber`s aspect ratio, location and orientation relative to the solid wall.
- OSTI ID:
- 110071
- Report Number(s):
- CONF-940659-; ISBN 0-7918-1372-X; TRN: IM9543%%373
- Resource Relation:
- Conference: 1994 American Society of Mechanical Engineers (ASME) Fluids Engineering Division summer meeting, Lake Tahoe, NV (United States), 19-23 Jun 1994; Other Information: PBD: 1994; Related Information: Is Part Of Liquid-solid flows 1994. FED Volume 189; Roco, M.C.; Crowe, C.T.; Joseph, D.D.; Michaelides, E.E. [eds.]; PB: 263 p.
- Country of Publication:
- United States
- Language:
- English
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