Abstract
An approximate equation for the drag coefficient of spherical particles is proposed in the form of a quadratic equation in logarithmic co-ordinates. The constants of the equation have been determined by the least square method from experimental values5). This equation gives better agreement with experimental values than the equations proposed previously by other authors. The constants of the equation and the comparison of its accuracy are summarized in Tables I and 2. This equation is valid even at Reynolds numbers between O and 70, 000, the standard deviation of the relative error being 5%.
