1. n. [Enhanced Oil Recovery]

A dimensionless group used in analysis of fluid flow that characterizes the ratio of gravitational forces to surface or interfacial tension forces. It is usually denoted N_b in the oil field and Bo in chemical engineering. A value of N_b <<1 implies the flow in question is only weakly dependent on gravitational forces, whereas N_b >>1 implies gravitational forces dominate over interfacial forces.

Bond number equation:

N_b = Bo = (Δρ g b²) / σ,

where

• N_b = Bo = Bond number
• Δρ = density difference between the two phases
• g = acceleration due to gravity
• b = a characteristic length scale of the flow geometry
• σ = surface or interfacial tension.

Synonyms: Eötvös number