Abstract
In this article, we investigate the time-periodic pulse electroosmotic flow (EOF) of Jeffreys fluids through a microannulus. By using the Laplace transform method, the velocity expression of the pulse EOF is derived. The effect of some variables on the time it takes for the fluid to go from a static state to a flowing state is analyzed. We find that increasing the relaxation time
λ
¯
1
{\bar{\lambda }}_{\text{1}}
and decreasing the inner and outer radius ratio
α
\alpha
will result in longer time for the fluid to reach the flowing state, but the retardation time
λ
¯
2
{\bar{\lambda }}_{\text{2}}
and the inner and outer zeta potential ratio
β
\beta
have little effect on it. The impact of some related parameters on the pulse EOF velocity for different inner and outer radius ratios (
α
\alpha
) is discussed in detail. The results show that for a smaller inner and outer radius ratio
α
\alpha
, the velocity amplitude increases with the relaxation time
λ
¯
1
{\bar{\lambda }}_{\text{1}}
and decreases with the retardation time
λ
¯
2
{\bar{\lambda }}_{\text{2}}
. As the inner and outer radius ratio
α
\alpha
increases, the effect of relaxation time
λ
¯
1
{\bar{\lambda }}_{\text{1}}
on velocity amplitude gradually weakens or even becomes insignificant, and the effect of the retardation time
λ
¯
2
{\bar{\lambda }}_{\text{2}}
on the velocity amplitude remains unchanged. Moreover, the velocity amplitude will decrease with the increase in the inner and outer radius ratio
α
\alpha
and its change range will expand from the electric double layer near the annular wall to the entire flow region.