1982 Volume 23 Issue 12 Pages 513-518
In order to analyse quantitatively the washing behavior of liquid flow to fabrics, it is studied to obtain the liquid drag coefficient of fabrics by using a falling method in which a specimen falls freely in a still liquid.
A theoretical treatment of fabrics falling freely in a still liquid has shown that the liquid drag coefficient of fabrics is proportional to the falling time squared, the error of the estimated liquid drag coefficient of fabric being twice the error of falling time. The treatment has also shown that a fabric falls at the terminal velocity after travelling 10 cm from the beginning of its falling.
The experiment in which fabrics were let to fall freely in a still liquid shows that the drag coefficient of fabrics is 1-3 for water, irrespective of the kind of fabrics, if the falling velocity is 1-30 cm/s, the fabric surface area vertical to the direction of falling being 1-25cm2, water temperature beings18°C. The experiment has also shown that for an aqueous solution of detergent, the drag coefficient is slightly higher.
