Wind Noise Control: How to Keep Cars Silent Above 150 km/hr

A: A: Absorber layers are called out with material specs, not generic hatching. No BOM link here. B: Datum misuse. You're controlling profile to edges that move with trim variation, so as-built drift is invisible on paper. That maps to field noise. C: Flatness controls the wrong thing; local waviness drives leakage. D: Knurling would be explicit and dimensioned, not implied by hatch.

A: A: You’ve already contaminated the baseline by taping too early. B: Cold inspection catches compression set, tape isolates leakage paths, soak checks material relaxation. Right order. C: That’s design, not verification. You’re skipping evidence. D: Yaw amplification hides straight-line leakage mechanisms.

A: A: Missed the length term; that speed gives Re an order low. B: Used 0.2 m instead of 0.12 m. C: Correct substitution and unit handling. That’s right in the 150+ km/hr complaint zone. D: Density correction double-counted.

A: A: Boundary layers don’t care about seal friction. B: Smaller gap, higher jet velocity. That’s your whistle. C: Drag and noise don’t scale linearly with leakage. D: High-speed pressure delta makes gaps louder, not quieter.