Fluid Dynamics Lecture II
, Types of Forces
• Body Force: distributed • Surface Force: Forces
over the entire mass or exerted on the fluid
volume of the element. It element by its
is usually expressed per surroundings through
unit mass of the element direct contact at the
or medium upon which surface.
the forces act. – Normal Force: along the
Example: Gravitational normal to the area
Force, Electromagnetic – Shear Force: along the
force fields etc. plane of the area.
If b be the body forceper unit mass If f be the surface per unit area , then total
then total body force : b dV surface force f .nˆ dS
S
V
, Types of Forces
• Body Force: distributed • Surface Force: Forces
over the entire mass or exerted on the fluid
volume of the element. It element by its
is usually expressed per surroundings through
unit mass of the element direct contact at the
or medium upon which surface.
the forces act. – Normal Force: along the
Example: Gravitational normal to the area
Force, Electromagnetic – Shear Force: along the
force fields etc. plane of the area.
If b be the body forceper unit mass If f be the surface per unit area , then total
then total body force : b dV surface force f .nˆ dS
S
V
