Theory 01/Acoustofluidics
Sorting Is a Force Ratio
The claim
Acoustic cell sorting resolves populations when the ratio of acoustic radiation force to viscous drag exceeds a threshold, so resolution is set by the ratio rather than by drive amplitude.
01The mechanism
A cell moves when the acoustic force exceeds the drag resisting it; the ratio determines whether a size difference produces a resolvable displacement.
02Predictions
- P1Resolution should track the force ratio.
- P2Amplitude alone should mispredict at different flow rates.
03Refutation
Resolution tracking amplitude would remove the ratio.