PEP 294: Lecture Notes
XV. Fluid Biomechanics
1. Buoyancy (pp. 510-514)
 | Buoyant force: |
- vertical force (upward) acting on an object immersed in a fluid
| Archimedes' Principle: |
- buoyant force is equal to the weight of the fluid displaced by the body
- (volume)(density of fluid)
- standard unit: N
- center of volume = center of buoyancy
| Flotation: |
- flotation: max buoyant force >= weight
- equilibrium when buoyant force = weight
- center of gravity vs. center of buoyancy
2. Drag (pp. 514-523)
| Drag vs. Lift: |
- drag: braking force acting on the object in the direction opposite to the motion
- lift: force acting on the object in the direction perpendicular to motion
| Drag: |
- proportional to (velocity)2
- surface drag:
(a) due to skin friction
(b) smoothness of the surface: texture, hair, etc.
(c) viscosity
- form drag:
(a) due to pressure differential
(b) streamlining
3. Lift (pp. 523-530)
| Lift: |
- force acting in the direction perpendicular to the motion
- proportional to (velocity)2
| Angle of Attack: |
- lift/drag ratio
- example: ski jumping
| Magnus Effect: |
- lift force created by spin
- causes curved path