Reliability-Based Criterion for Evaluating Explicit Approximations of Colebrook Equation

Numerous explicit approximations of the Colebrook equation have been developed and evaluated based on two criteria: prediction accuracy computational efficiency. This paper introduces a new evaluation criterion reliability each equation. The is defined by coefficient variation (CV) friction factor that function variabilities component random variables (roughness height internal pipe surface kinematic viscosity fluid). depends its first derivative for roughness inner fluid their correlation. Seven were using reliability-based criterion. results show all are very reliable, but variations exist regarding level. reliabilities seven close rough-flow regime when CV minimal. However, smooth-flow regime, minimal, various showed substantially different reliabilities. novelty proposed it addresses an dimension complements efficiency criteria.