Abstract
2020The drag coefficient of porous materials in slow flow is examined theoretically and experimentally. A theoretical solution for a three-dimensional Oseen's equation is obtained by using a variational consideration and the cell model. From this solution, the drag coefficient is determined as a function of Reynolds number and volume fraction. Theoretical results are compared with experimental ones obtained by using spheres or a coil model as a porous material. It is found that the theoretical analysis is available for Oseen's equation and that the upper limit of effective region for Reynolds number is about 30. The value of drag coefficient for a general porous material from 2-dimensional theory.