Abstract:
|
We have studied the kinetic roughening of an oil-air interface in a forced imbibition experiment in a horizontal Hele-Shaw cell with quenched disorder. Different disorder configurations, characterized by their persistence length in the direction of growth, have been explored by varying the average interface velocity
v
and the gap spacing b. Through the analysis of the rms width as a function of time, we have measured a growth exponent
β
≃
0.5
that is almost independent of the experimental parameters. The analysis of the roughness exponent
α
through the power spectrum has shown different behaviors at short
(
α
1
)
and long
(
α
2
)
length scales, separated by a crossover wave number
q
c
.
The values of the measured roughness exponents depend on experimental parameters, but at large velocities we obtain
α
1
≃
1.3
independently of the disorder configuration. The dependence of the crossover wave number with the experimental parameters has also been investigated, measuring
q
c
∼
v
0.47
for the shortest persistence length, in agreement with theoretical predictions. |