# Bond Number

Written by Jerry Ratzlaff on . Posted in Dimensionless Numbers

Bond number, abbreviated as Bo, a dimensionless number, represents the relationship of gravitational force to surface tension force.  In Europe, the Bond number is known as the Eötvös number, abbreviated as Eo.  When used with the Morton Number, it is used to characterize the shape of bubbles or drops moving within a fluid.

## Bond Number formula

$$\large{ Bo = \frac{ \rho \; a \; l^2}{\sigma} }$$
Symbol English Metric
$$\large{ Bo }$$ = Bond number $$\large{dimensionless}$$
$$\large{ a }$$ = acceleration $$\large{\frac{ft}{sec^2}}$$ $$\large{\frac{m}{s^2}}$$
$$\large{ \rho }$$  (Greek symbol rho) = density $$\large{\frac{lbf}{in^2}}$$ $$\large{Pa}$$
$$\large{ l }$$ = length $$\large{in}$$  $$\large{mm}$$
$$\large{ \sigma }$$ = surface tension  $$\large{\frac{lbf}{ft}}$$  $$\large{\frac{N}{m}}$$