Fluid Motion Flashcards
What are Fluids ?
They are a substance that assumes the shape of the vessel in which it is contained; a substance that tends to flow, gases and liquids.
What is Buoyancy
The upward buoyant force that is exerted on a body in water and if it is equal to the weight of the fluid that the body displaces you float.
What is Drag ?
The force that acts in the opposite direction to the direction of motion of an object.
Drag (Fact Card!)
When molecules collide with an object they take energy away from it.
- All moving objects have kinetic energy. If energy is taken away from them, their mass, or their velocity must decrease.
- The mass normally stays the same so the object loses velocity.
What is Efficiency ?
The measure of how much energy is wasted by a particular process.
What is Laminar Flow ?
Laminar flow is characterised by smooth parallel fluid layers (the fluid follows nicely by the side of the object). Occurs when the object is small or the velocity is low.
What is Turbulent flow ?
Occurs when the object moves with high velocity relative to the fluid. Turbulent flow is characterised by a turbulent pocket behind the object.
What are Eddies ?
A turbulence that occurs in the wake of an object. Eddies appear like small whirlpools of water or air. Energy is taken from a object to form the eddies, hence slowing the object down.
They cause more slowing down of the body than either form drag or surface drag. Reduced by making objects ‘streamlined.’
What is Form Drag ?
The resistance that decelerates an object’s movement through a fluid and is created when boundary layer becomes turbulent behind the object.
What is Drafting ? (Team Persuit)
Reduces form drag on the followers because the leader creates a pocket of reduced pressure allowing riders in group to expend 40% less energy than solo riders.
What is the Magnus effect ?
A deviation in the trajectory of a spinning object toward the direction of the spin.
