Fluid Motion Equations

Question 1

Buoyancy

Answer 1

• A fluid force that always acts vertically upward
• F(b) = V(d)γ
• F(b) = buoyant force
• V(d) = displaced volume
• γ = fluid’s specific weight

Question 2

Drag Force

Answer 2

• A force caused by the dynamic action of a fluid that acts in the direction of the fluid flow
• F(D) = ½ C(D) ρ A(p) v²
• F(D) = Drag force
• C(D) = coefficient of drag
• ρ = fluid density
• A(p) = surface area
• v = velocity of the body relative to the fluid

Question 3

Lift Force

Answer 3

• Force acting on a body in a fluid in a direction perpendicular to the fluid flow
• F(L) = ½C(L)ρA(p)v²
• F(L) = lift force
• C(L) = coefficient of lift
• ρ = fluid density
• A(p) = surface area
• v = velocity of the body relative to the fluid