fluid mechanics Flashcards
What is Fluid Resistance?
Fluid resistance is the force that opposes the motion of an object through a fluid (liquid or gas), such as water or air. It is made up of surface drag and form drag.
What is Surface Drag?
Surface drag (or skin friction) is caused by the friction between a fluid and the surface of a moving object. It depends on surface smoothness and fluid viscosity.
What is Form Drag?
Form drag (or pressure drag) is caused by the shape of the object and the pressure difference between the front and back as it moves through fluid.
Laminar vs Turbulent Flow
Laminar flow is smooth and parallel fluid flow, creating less resistance.
Turbulent flow is chaotic and irregular, increasing drag.
Importance of Streamlining
Streamlining reduces turbulence and form drag, allowing the athlete or object to move more efficiently through a fluid.
What factors increase drag in swimming?
Rough swimsuit materials
Poor technique (wide arm recovery, head up)
Lack of streamlining
Longer hair or accessories
What factors increase drag in cycling?
Upright body position
Loose clothing
Large frontal surface area
Crosswinds
How can swimmers reduce drag?
Wear full-body, smooth swimsuits (e.g., Fastskin suits)
Shave body hair
Maintain a horizontal streamlined position
Use efficient technique (e.g., clean entry)
How can cyclists reduce drag?
Aerodynamic helmets and tight lycra suits
Tuck into a low, aerodynamic position
Use aerodynamic bike frames and wheels
Draft behind other cyclists (slipstreaming)
