The Angle of Repose

One of the better references regarding basic hydraulics is a book published in 1943 – Audels Pumps, Hydraulics, Air Compressors: A Practical Treatise by Frank D. Graham. Here is an interesting graphics showing the “angle of repose” for a typical pile of material. The “angle of repose” is defined as”The greatest angle with the horizontal at which a mass material as in an embankment of coal pile will lie without sliding. The angle varies for different materials.”