hydraulic friction[hī′drȯ·lik ′frik·shən]
Resistance to flow which is exerted on the surface of contact between a stream and its conduit and which induces a loss of energy.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The friction that resists the flow of a fluid along the piping or ductwork in which it is conveyed and at obstructions.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.