Minutes of Proceedings of the Institution of Civil Engineers Volume N . 80

Minutes of Proceedings of the Institution of Civil Engineers Volume N . 80

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This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1885 edition. Excerpt: ... disk-shaped surfaces in the water round them. Suppose a thin circular disk, mounted on a vertical spindle, and rotated at constant velocity in a cylindrical vessel of water. Two methods are available for measuring the resistance to rotation of the disk. One is to measure by dynamometric apparatus the work expended in moving the disk. The objections to this method are the complexity of the apparatus, and the difficulty of eliminating other frictional resistances, such as those of the bearings of the spindle. The other method is to measure the force with which the vessel in which the disk is contained tends to rotate. The friction of the water on the vessel must be equal and opposite to the friction on the disk, when the motion is uniform. This method, the Author believes, was first employed by Professor James Thomson, in some experiments on the friction of disks, the results of which were communicated to the Royal Society1 in 1855. The details of Professor Thomson's experiments have not been published, and the conditions in these experiments do not appear to have been much varied. Their general result is stated thus: --For disks with both sides rubbing in water in a flat surrounding chamber, the work expended in fluid friction is given by the equation y3d Z 90,000' where z = work expended in foot-lbs. per minute--d = diameter of disk in feet. y = number of rotations per minute. It is obvious that the constant here found is applicable only to one condition of surface. Description of the Apparatus.--The apparatus used by the Author is shown in an isometric view in Plate 3, Fig. 1, and in sectional elevation and plan in Figs. 2, 3. It consisted of a strong wooden frame, on which was placed a cast-iron cistern C. A cast-iron bracket B at the top of..show more

Product details

  • Paperback | 174 pages
  • 189 x 246 x 9mm | 322g
  • Rarebooksclub.com
  • Miami Fl, United States
  • English
  • black & white illustrations
  • 1236500016
  • 9781236500014