Question

The proportionality factor in the Darcy's equation is known as:

• A. Hydraulic gradient
• B. Flux density
• C. Hydraulic conductivity
• D. Thermal conductivity

Hint:

Darcy's Law is analogous to:
- Ohm's Law in electricity (\( I = \frac{V}{R} \))
- Fourier's Law in heat transfer (\( q = -k \nabla T \))
In all these transport equations, flux is equal to a conductivity factor multiplied by a driving gradient.

Answer 1

The Correct Option is C

Step 1: Understanding the Concept:
Darcy's Law describes the flow of a fluid through a porous medium (such as water flowing through a soil column).
Detailed Explanation:
- Darcy's equation is mathematically written as:
\[ V = K \cdot \frac{\Delta H}{L} \] or
\[ q = K \cdot i \] where:
- $V$ (or $q$) is the discharge velocity or flux density.
- $i = \frac{\Delta H}{L}$ is the hydraulic gradient (head loss per unit flow length).
- $K$ is the constant of proportionality.
- This proportionality factor, $K$, represents the ease with which a soil allows water to flow through its pores.
- In soil physics and fluid mechanics, this parameter is termed the ______Hydraulic conductivity______.
- The hydraulic gradient ($i$) is the driving force.
- Flux density is the flow rate per unit area ($q$).

Step 2: Final Answer:
The proportionality factor is known as the hydraulic conductivity, corresponding to option (C).