The flow resistance characteristics of the pulsating flow in the triangular channel with different plate spacings were studied with water as the working fluid. Based on the force balance equation

a mathematical model suitable for the pulsating flow pressure drop of the triangular channel is established to theoretically analyze the influencing factors of the flow resistance. Mathematical model shows that flow resistance is mainly affected by channel height and enstrophy. Flow resistance increases as channel height reduces

but increases with enstrophy. In addition

experiment and numerical research have been conducted to investigate correlation among channel height

enstrophy and flow resistance. The experimental results show that flow resistance becomes large as the channel height becomes short. What's more

when the ratio of channel height and groove depth is less than 1.0

the sharp rise of flow resistance occurs. And flow resistance increases ten fold compared with the state that the ratio of channel height and groove depth is more than 1.0. Otherwise

no matter how the channel height changes

resistance also increases with pulsating amplitude

and there exists a Womersley number for the highest flow resistance. The numerical results indicate that the reason why flow resistance changes dramatically as the channel height decreases is because flow field changes with the channel height. When the ratio of channel height and groove depth is more than 1.0

vortex is mainly located inside the triangle groove. Thus the wall of mainstream can be rarely affected. However

when the ratio of channel height and groove depth is less than 1.0

vortex in the triangle groove expands and gradually affects the area of mainstream. Hence the flow separation occurs near the wall of mainstream

which causes wave flow and eddy coexisting.