Custom Search
Lift and Drag
Body in fluid flow - lift and drag
Sponsored Links
Lifting Force
The lifting force acting on a body in fluid flow can be expressed as
L = cL 1/2 ρ v2 A (1)
where
L = lifting force (N)
cL = lifting coefficient
ρ = density of fluid (kg/m3)
v = flow velocity (m/s)
A = body area (m2)
Drag Force
The drag force acting on a body in fluid flow can be expressed as
D = cD 1/2 ρ v2 A (2)
where
D = drag force (N)
cD = drag coefficient
ρ = density of fluid (kg/m3)
v = flow velocity (m/s)
A = body area (m2)
Required Thrust Power to overcome Drag Force
Required thrust power to overcome the drag force can be calculated as
P = D v (3)
where
P = power (W)
Example Aeroplane - Lift, Drag and required Thrust Power
For an aeroplane with velocity 100 m/s, wing area 20 m2, drag coefficient 0.06 and lift coefficient 0.7, the lifting force can be calculated as
L = 0.7 1/2 (1.2 kg/m3) (100 m/s)2 (20 m2)
= 84000 N
= 84 kN
The drag force can be calculated as
D = 0.06 1/2 (1.2 kg/m3) (100 m/s)2 (20 m2)
= 7200 N
= 7.2 kN
Required thrust power to overcome the drag force:
P = (7200 N) (100 m/s)
= 720000 W
= 720 kW
Sponsored Links
Search the Engineering ToolBox
Custom Search
Engineering ToolBox - SketchUp Edition - Online 3D modeling!
Engineering ToolBox - SketchUp Edition - enabled for use with the amazing, fun and free Google SketchUp