Which term describes a flow profile where velocity distribution causes a broad spectral display?

• A. Parabolic flow profile
• B. Laminar flow profile
• C. Plug flow profile
• D. Spectral broadening flow profile

Answer: (D)

The main idea is that the width of a spectral display directly reflects how velocities vary across the flow. When different parts of the cross-section move at different speeds, the resulting spectrum broadens because you’re effectively combining many Doppler shifts or frequency components. The term that explicitly describes a flow where this velocity distribution causes a broad spectral display is the spectral broadening flow profile.

If the flow were plug flow, all particles have almost the same velocity, so the spectrum would be narrow. A parabolic flow profile has a gradient of speeds from the wall to the center, which broadens the spectrum to some extent, but the descriptor that specifically denotes broad spectral display due to velocity spread is the spectral broadening flow profile.