Reynolds Number

- Engineering & Applied Technologies -
Aerospace & Automotive Dictionary
Definition

A physical design concept defining how aerodynamic forces and structural behavior are modeled, tested, and managed in flight or vehicle applications. It governs performance prediction, load sizing, and durability assessment using analysis and test evidence. It does not provide acceptable performance without appropriate design margins and validated models for the intended operating envelope.

Reynolds Number

Natural & Formal Sciences Dictionary
Definition
A dimensionless ratio Re = U L / ν that compares inertial to viscous forces in a fluid, where U is a characteristic velocity, L a characteristic length, and ν the kinematic viscosity.

Reynolds Number

Engineering & Applied Technologies Dictionary
Definition
A dimensionless quantity Re = ρ V L / μ (or Re = V L / ν) that expresses the ratio of inertial forces to viscous forces in a continuum fluid flow; it characterizes whether flow behavior is dominated by momentum advection or viscous diffusion for a chosen characteristic length L and velocity scale V under Newtonian, continuum conditions.