Transient cavitation is most likely to occur under which condition?

• A. Long Duration Pulses
• B. High Pressure, Short Pulses
• C. Low Frequency Continuous
• D. Low Amplitude

Answer: (B)

Transient cavitation occurs when the ultrasound field creates a very large peak negative pressure during the rarefaction part of a pulse, causing microbubbles to rapidly grow and then violently collapse. This inertial cavitation is driven by high pressure amplitude and short pulse duration: the bubbles form and collapse quickly within a few cycles, producing energetic effects. If the pulses are long, gas diffusion and stabilization can occur between cycles, reducing the likelihood of a violent collapse. Low amplitude wouldn’t nucleate bubbles, and a continuous wave at low amplitude doesn’t provide the short, high-amplitude burst needed for transient cavitation. So the combination of high pressure and short pulses best promotes transient cavitation.