After solving the mathematical model of fluid unsteady flow for a horizontal well in 3D circular-boxed media,a novel equivalent radius model was presented by asymptotic analyses to the solution.

Test of the capillary equivalent radius of yarn;

A unit model for fiber tows was built to simulate the value and distribution of equivalent radius of capillary voids in profiled polyester fiber tows with circular, square, triangular and double-crossed cross sections by using the self-developed fiber tow cross section mathematical simulation software.

From the study of relation between specimen' s shape and plastic indicator for isotropic material, the concept of equivalent diameter is introduced, and the quantitative relationship between plastic indicator and the ratio of gauge length to equivalent diameter is established.

The experimental data of pressure drop was used to calculate equivalent diameter d s by Ergun formula.

This paper studied the influence of irregular shape catalysts with through-holes on the pressure drop of the fixed bed and determined the equivalent diameter of irregular shape catalysts with through-holes.

Using scour data downstream of the spillway obtained from prototype observation of a completed project, an inverse model test is conducted so as to determine the proper equivalent particle sizes of scour resistance in the model.