1. What is Proportionate Velocity?

Proportionate Velocity is the ratio of velocity when water is partially full to velocity when water is totally full. It's used in hydraulic engineering to determine flow characteristics in partially filled pipes or channels.

2. How Does the Calculator Work?

The calculator uses the Proportionate Velocity formula:

Where:

• \( Pv \) — Proportionate Velocity
• \( rpf \) — Hydraulic Mean Depth for Partially Full (m)
• \( Rrf \) — Hydraulic Mean Depth while Running Full (m)

Explanation: The formula calculates the velocity ratio based on the hydraulic mean depth ratio raised to the power of 2/3, assuming roughness coefficient remains constant with depth.

3. Importance of Proportionate Velocity Calculation

Details: Calculating proportionate velocity is essential for designing efficient drainage systems, irrigation channels, and sewer systems where pipes operate at partial capacity.

4. Using the Calculator

Tips: Enter hydraulic mean depth values in meters. Both values must be positive numbers greater than zero for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: When is this formula applicable?
A: This formula applies when the roughness coefficient does not vary with depth, which is typically true for uniform pipe materials.

Q2: What is hydraulic mean depth?
A: Hydraulic mean depth is the cross-sectional area of flow divided by the wetted perimeter, representing the efficiency of the flow section.

Q3: Can this formula be used for all pipe shapes?
A: The formula works best for circular pipes but can provide reasonable approximations for other shapes with proper hydraulic radius calculations.

Q4: What are typical values for proportionate velocity?
A: Proportionate velocity typically ranges between 0 and 1, with values closer to 1 indicating flow conditions closer to full capacity.

Q5: How does depth affect flow velocity?
A: As depth increases toward full capacity, flow velocity generally increases due to reduced frictional losses relative to the flow area.