| Prandtl number [`pränt·ǝl ´nǝm·bǝr] FLUID MECHANICS A dimensionless number used in the study of diffusion in flowing systems, equal to the kinematic viscosity divided by the molecular diffusivity. Symbolized Prm . Also known as Schmidt number 1 (NSc ). THERMODYNAMICS A dimensionless number used in the study of forced and free convection, equal to the dynamic viscosity times the specific heat at constant pressure divided by the thermal conductivity. Symbolized NPr . |