What term describes the friction between water and the hose interior?

What term describes the friction between water and the hose interior?

• A. Viscosity
• B. Coefficient of friction
• C. Turbulence
• D. Drag coefficient

Answer: (B)

Friction at the boundary where water slides along the hose interior is described by viscosity. Viscosity is the fluid’s internal resistance to shear; as water layers move at different speeds, layers near the wall shear the adjacent layers, producing a tangential stress proportional to the velocity gradient through τ = μ(dv/dy). This wall shear governs the friction losses you experience as water flows through the hose, affecting pressure drop and flow rate. The other terms don’t fit as the description of this boundary friction: the coefficient of friction is used for sliding between solid surfaces, not the internal resistance within a fluid; turbulence refers to chaotic flow behavior that can influence losses but is not the friction itself; and the drag coefficient characterizes resistance on an object in a flow, not the intrinsic wall friction of a fluid against a pipe.

Friction at the boundary where water slides along the hose interior is described by viscosity. Viscosity is the fluid’s internal resistance to shear; as water layers move at different speeds, layers near the wall shear the adjacent layers, producing a tangential stress proportional to the velocity gradient through τ = μ(dv/dy). This wall shear governs the friction losses you experience as water flows through the hose, affecting pressure drop and flow rate.

The other terms don’t fit as the description of this boundary friction: the coefficient of friction is used for sliding between solid surfaces, not the internal resistance within a fluid; turbulence refers to chaotic flow behavior that can influence losses but is not the friction itself; and the drag coefficient characterizes resistance on an object in a flow, not the intrinsic wall friction of a fluid against a pipe.