Drag Force Exerted By Flowing Water Calculator

Drag Force Formula:

\[ F_D = \gamma_w \times (G-1) \times (1-n) \times t \times \sin(\alpha_i) \]

Unit Weight of Fluid (γw):

N/m³

Specific Gravity of Sediment (G):

Rugosity Coefficient (n):

Volume per Unit Area (t):

Angle of Inclination (αi):

degrees

Drag Force (F_D):

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1. What is Drag Force?

Drag Force is the resisting force experienced by an object moving through a fluid. In the context of flowing water, it represents the force exerted by water on sediment particles or other submerged objects.

2. How Does the Calculator Work?

The calculator uses the Drag Force formula:

\[ F_D = \gamma_w \times (G-1) \times (1-n) \times t \times \sin(\alpha_i) \]

Where:

\( F_D \) — Drag Force (N)
\( \gamma_w \) — Unit Weight of Fluid (N/m³)
\( G \) — Specific Gravity of Sediment
\( n \) — Rugosity Coefficient
\( t \) — Volume per Unit Area (m)
\( \alpha_i \) — Angle of Inclination of Plane to Horizontal (degrees)

Explanation: The equation calculates the force exerted by flowing water on sediment particles, accounting for fluid properties, sediment characteristics, surface roughness, and slope angle.

3. Importance of Drag Force Calculation

Details: Accurate drag force estimation is crucial for predicting sediment transport, designing erosion control measures, and understanding river morphology and coastal processes.

4. Using the Calculator

Tips: Enter all values with appropriate units. The unit weight of water is typically 9810 N/m³. Angle should be between 0-90 degrees. All values must be positive.

5. Frequently Asked Questions (FAQ)

Q1: What is the typical value for unit weight of water?
A: For freshwater at standard conditions, the unit weight is approximately 9810 N/m³ (or 62.4 lb/ft³ in imperial units).

Q2: How is specific gravity of sediment determined?
A: Specific gravity is the ratio of sediment density to water density. For most natural sediments, it ranges from 2.5 to 2.7.

Q3: What does the rugosity coefficient represent?
A: The rugosity coefficient (n) quantifies surface roughness, with values ranging from 0.01 (smooth surfaces) to 0.06 (very rough surfaces).

Q4: When is this drag force equation applicable?
A: This equation is particularly useful in sediment transport studies and hydraulic engineering for estimating forces on sediment particles in flowing water.

Q5: How does angle of inclination affect drag force?
A: Drag force increases with the sine of the inclination angle, reaching maximum at 90 degrees (vertical surface).