The short answer is yes, and many companies use this as a basis for computer aided design packages, with appropriate constants introduced for each and every new material and grade of material. Without the constants it can only be used as a first approximation or quick check method. I have a complete write up and derivation from first principles of this in chapter 16 of my book - the Handbook of Pneumatic Conveying Engineering (with colleagues Jones and Agarwal) - ISBN 0-8247-4790-9 published in 2004 by Marcel Dekker (now CRC Press - part of the Taylor & Francis Group). ■