Bond number, Bo, is a dimensionless group which arises from the analysis of the behavior of Bubbles and Drops. It is represented as:
where g is the acceleration due to gravity; ρL, the liquid density; ρG, the gas density; σ, the interfacial surface tension; and L is the appropriate linear dimension, e.g., bubble diameter.
It represents the ratio of gravitational force to surface tension force.
This same group is sometimes referred to as the Iötvös number.