1. What is the Velocity Calculation Formula?

The formula calculates velocity in a partially running sewer by multiplying the full-flow velocity by the proportionate velocity ratio. This provides the actual flow speed when the sewer isn't completely filled.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( V_s \) — Velocity in a Partially Running Sewer (m/s)
• \( V \) — Velocity While Running Full (m/s)
• \( P_v \) — Proportionate Velocity (dimensionless)

Explanation: The formula accounts for reduced flow speed when a sewer isn't completely filled, using the proportionate velocity ratio to scale down the full-flow velocity.

3. Importance of Velocity Calculation

Details: Accurate velocity calculation is crucial for designing sewer systems, ensuring proper flow rates, preventing sediment deposition, and maintaining self-cleansing velocities in partially filled conditions.

4. Using the Calculator

Tips: Enter full-flow velocity in m/s and proportionate velocity (dimensionless ratio). Both values must be positive numbers for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: What is proportionate velocity?
A: Proportionate velocity is the ratio of velocity when water is partially full to velocity when water is totally full in a sewer pipe.

Q2: Why is velocity important in sewer design?
A: Proper velocity prevents sediment accumulation, ensures self-cleansing action, and maintains efficient wastewater transport in sewer systems.

Q3: What factors affect velocity in partially filled sewers?
A: Pipe slope, roughness, flow depth, and cross-sectional area all influence the velocity in partially running conditions.

Q4: What are typical velocity ranges in sewer systems?
A: Typically 0.6-3 m/s to prevent sedimentation at low velocities and avoid pipe erosion at high velocities.

Q5: How does partial flow affect velocity?
A: Partial flow generally reduces velocity compared to full flow due to increased friction and reduced hydraulic radius.