Interactions between contacting and colliding particles associated with energy dissipation mainly dominate sediment transport under oscillatory sheet-flow regime, where hysteretic-dependent complicated behavior dominates over periodical one due to a change in microscopic particle configuration even under the fully periodically oscillatory external forces. Difference in response time between solid particle and carrier phase to oscillatory flow furnish momentum transfer, resulting phase-dependent particle stress should be estimated to ascertain detail mechanism of the sheet-flow regime. In the present study, particle velocity under oscillatory flow is extracted from video sequence taken through the sidewall, accordingly phase-dependent particle shear stress is revealed.
