AbstractDispersed particles tend to migrate in a preferred direction in a pulsed liquid flow in the presence of fixed baffles of asymmetric design. Conical and inclined disc baffles were found to promote migration of dense materials (sand, hematite) up an inclined length of 5.08 cm. diameter pipe. Conical baffles were effective in increasing the gas holdup in a vertically pulsed bubble column, provided the thick end of the cone was uppermost. These effects are thought to be due to the entrainment of the dispersed phase into separation vortices. Energy dissipation measurements with conical baffles are consistent with this model.