On Fluffing of Cards

[+] Author and Article Information
S. M. Desai

Sperry Univac, Research and Advanced Technology, Blue Bell, Pa.

J. Fluids Eng 96(3), 227-233 (Sep 01, 1974) (7 pages) doi:10.1115/1.3447145 History: Received February 07, 1974; Online October 12, 2010


When a stack of identical thin cards is placed in a straight rectangular channel so that the planes of the cards are parallel to the channel axis and an air flow is started, it is observed that under suitable conditions the cards get separated from the walls and each other if they are free to do so. This is called fluffing of cards. A two-dimensional analysis based on an application of the principle of minimum dissipation to viscous flows through card gaps is presented to explain the dynamical behavior of the fluffed cards. It is found that the state of uniform distribution is not only the state of static equilibrium but also, the state of absolute minimum viscous energy dissipation. The analysis determines the forces tending to separate the cards and then the equations for small amplitude oscillations of the cards about the state of uniform distribution. These equations are solved for corresponding modes and frequencies.

Copyright © 1974 by ASME
Your Session has timed out. Please sign back in to continue.






Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In