Longitudinal Wave
In a longitudinal or compression wave, the particles move forth and back parallel to the direction of the wave.
- A pulse is sent to the piezoelectric element, the element expands and produces a longitudinal wave
- The particles move parallel to the direction of the wave
Longitudinal waves are less affected by grain structure than compression waves due to their longer wavelength. This is the reason longitudinal waves are often use for stainless steel inspections.