1987 Volume 30 Issue 270 Pages 1928-1934
The drag coefficient of porous materials in slow flow is examined theoretically and experimentally. A theoretical solution for a three-dimensional Ossen'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 the Reynolds number and the volume fraction. Theoretical results are compared with the experimental ones obtained by using spheres or a coil model as porous materials. It is found that theoretical analysis is available for Ossen's equation and that the upper limit of the effective range for the Reynolds number is about 30. The value of the drag coefficient for general porous materials seems to lie in the region between those obtained from two-and three-dimensional theory.