If A_v is the area of voids in cross-section and A is the total area of cross-section, the relation between seepage velocity (v_s ) and superficial velocity (v) is correctly represented as:

Explanation:

• Seepage velocity (vs): This is the velocity at which the fluid actually moves through the voids in the material.

• Superficial velocity (v): This is the velocity of the fluid if it were to move through the entire cross-sectional area (including both the solid and void portions of the material).

The relationship between seepage velocity and superficial velocity is given by the equation: v = Avvs/A

Where:

• A_v $A_v$ ​ is the area of voids in the cross-section.

• A $A$  is the total area of the cross-section (including both solids and voids).

• v_s $v_s$  is the seepage velocity.

• v $v$  is the superficial velocity.

Additional InformationSeepage Velocity

• Definition: Seepage velocity refers to the actual velocity of water or fluid that moves through the void spaces (pores) of a material, such as soil or a porous medium.

• Importance: It is used to understand how quickly fluid travels through the porous medium, which is crucial in applications like groundwater flow, soil permeability tests, and drainage.

• Relation to Porosity: Seepage velocity is dependent on the porosity and the permeability of the material. Higher porosity generally results in higher seepage velocity for the same hydraulic gradient.