Homogenization problems in fluid mechanics represent the study of fluid flows in domains perforated with a large number of small holes (or obstacles). The asymptotic behavior of the fluid flows as the number of holes goes to infinity and the size of holes goes to zero is the main concern. I will recall the background and some known results in this filed. Then I will present some recent studies on this topic, based on the collaborations with E. Feireisl, L. Diening, S. Schwazacher, and Y. Sun.