The movements of tracer particles in a labyrinth channel were observed by using the PIV
technique． The pressure was in dynamic modes with trigonometric function，triangular，step and
rectangular waveforms． The trajectories，velocity of single particle as well as the overall flow field in the
channel were analyzed to reveal the anti-clogging mechanism of dynamic water pressure． The results
showed that when compared with constant water pressure，flow rates in the channel under trigonometric
function，triangular，step and rectangular waveforms dynamic pressure modes were not decreased
significantly． Therefore，effect of dynamic water pressure on water delivery capacity of drip irrigation
system was not obvious． Among the different dynamic water pressure modes mentioned above，the
trigonometric function type demonstrated the shortest particles residence time in the flow stagnation
region． The deposition probability of particles was the lowest under this mode，indicating a better
particles transport capacity in the channel． Fluctuation effect generated by the water under pressure of
trigonometric function form produced effect on the low-speed swirl in the stagnation region，and
aggravated the turbulence of flow in this region． The turbulent flow was enhanced and the ability to carry
the particles retained or even deposited in the stagnation zone was improved． As a result，the particles
were suspended from the bottom and returned back to the main flow path． The transport capacity of the
flow got strengthened，and the anti-clogging performance of the channel was improved． Therefore，the
trigonometric function waveform dynamic water pressure model can most effectively improve the anti-
clogging performance in the labyrinth channel．
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