Sound reflecting off a hard boundary has zero particle velocity

Evidence

Looking at Figure 9.18(c) and (d) it is evident that pressure and particle velocity are inverses of each other. It is intuitively easy to understand that air molecules that are against a hard wall have nowhere to go, and particle velocity is zero. Equally instinctive is the notion that a sound pressure wave arriving at a rigid wall will build up pressure as it is unsuccessful at moving the wall and is reflected. So, at a reflecting boundary, pressure is at a maximum, and particle velocity is at a minimum. — Toole, Floyd E, Sound reproduction- the acoustics and…, 1024

Categorization

• DEFINE: Establishes the complementary relationship between sound pressure and particle velocity at boundaries.
• corroborated: 2 independent passages support this claim — Toole, Floyd E, Sound reproduction- the acoustics and…, 1024
• XREF: connects to: Sound wave molecules have zero velocity at compression peaks due to inertia; Hard boundaries reflect sound because pressure energy cannot cross a zero-velocity point.; At an open boundary, pressure equals zero while velocity doubles. (+1 more)

Broader Connections

• Hard boundaries reflect sound because pressure energy cannot cross a zero-velocity point. #corroborates (0.92)
• At an open boundary, pressure equals zero while velocity doubles. #corroborates (0.80)
• An open pipe end only reflects sound when an impedance mismatch exists there #qualifies (0.75)