Engineering Board Exam Reviewer · Fluid Mechanics · medium

The dimensionless number most important in modeling flow in closed pipes (no free surface) is the:

  1. Froude number
  2. Reynolds number
  3. Weber number
  4. Mach number

Answer

B. Reynolds number

Solution

Viscous forces dominate similarity for fully enclosed flows; gravity forces govern free-surface flows (Froude).

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