抄録
The horizontal air-flow method in which fibers fall freely in a horizontal air-flow is studied and their horizontal displacement is used to obtain the fineness distribution. This article describes a preliminary experiment and the theory of the descent of fibers.
The preliminary experiment in which fibers were let to fall in still air shows that the higher the fineness, the higher the velocity of falling. The experiment shows also that fibers of the same fineness vary only slightly in the velocity of their falling even if they differ in fiber length.
A theoretical treatment of fibers falling in a horizontal air-flow has shown clearly that the fibers initially fall with a terminal velocity, its horizontal displacement being proportional to (n-1)/4 power of fiber fineness, where n is a constant depending upon the posture of the fiber falling n is equal to -1.840 if fibers fall with their axes perfectly horizontal ; equal to -1.625 in case of a partially horizontal descent. These results show that it is possible to measure the fiber fineness distribution by the horizontal air-flow method.
