Buoyancy

Written by Jerry Ratzlaff on . Posted in Fluid Dynamics

buoyancy 1ABuoyancy, abbreviated as B, is when a liquid applies upward force on an object that is completely submerged or floating.

 

Buoyancy Types

  • Positive buoyancy - when the liquid force is greater than the object weight displacement.
  • Negative buoyancy - when the liquid force is less than the object weight displacement.
  • Neutral buoyancy - when the liquid force is equal to the object weight displacement.

 

Buoyancy formulas

\(\large{ B =  p \;A }\) 
\(\large{ B =  \rho\; V\; g }\) 
\(\large{ B =  \rho \;g \;h\; A }\) 

Where:

 Units English Metric
\(\large{ B }\) = buoyancy force \(\large{ lbf }\)  \(\large{N}\) 
\(\large{ V }\) = displaced volume \(\large{ ft^3 }\) \(\large{ m^3 }\)
\(\large{ \rho }\) (Gtrrk symbol rho) = fluid density \(\large{\frac{lbm}{ft^3}}\) \(\large{\frac{kg}{m^3}}\)
\(\large{ g }\) = gravitational acceleration  \(\large{\frac{ft}{sec^2}}\)    \(\large{\frac{m}{s^2}}\)    
\(\large{ h }\) = height of liquid displaced by a floating object \(\large{ ft }\)  \(\large{ m }\) 
\(\large{ p }\) = pressure \(\large{\frac{lbf}{in^2}}\)  \(\large{\frac{N}{m^2}}\)
\(\large{ A }\) = surface area of object  \(\large{ ft^2 }\) \(\large{ m^2 }\) 

 

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Tags: Equations for Liquid Equations for Hydraulic Equations for Buoyancy