1. What is Local Friction Coefficient?

Local Friction Coefficient for the flow in ducts is the ratio of wall shearing stress and dynamic head of the stream. It represents the local skin friction at a specific point along the surface.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( Cfx \) — Local Friction Coefficient
• \( Rex \) — Reynolds Number at distance X from the leading edge

Explanation: This formula calculates the local skin friction coefficient for laminar flow over a flat plate, where the flow is parallel to the plate surface.

3. Importance of Local Friction Coefficient Calculation

Details: Calculating local friction coefficient is crucial for determining drag forces on surfaces, analyzing fluid flow characteristics, and designing efficient fluid systems in various engineering applications.

4. Using the Calculator

Tips: Enter the Reynolds Number at the desired distance from the leading edge. The value must be valid (Rex > 0).

5. Frequently Asked Questions (FAQ)

Q1: What is the range of validity for this formula?
A: This formula is valid for laminar flow over a flat plate with Reynolds numbers typically below 5×10⁵.

Q2: How does local friction coefficient relate to total drag?
A: The total drag force can be obtained by integrating the local friction coefficient over the entire surface area.

Q3: What factors affect the local friction coefficient?
A: The coefficient depends on the Reynolds number, surface roughness, and flow conditions (laminar vs turbulent).

Q4: Can this formula be used for turbulent flow?
A: No, this specific formula is only valid for laminar flow. Different correlations exist for turbulent flow conditions.

Q5: How does the friction coefficient change along the plate?
A: The local friction coefficient decreases with increasing distance from the leading edge as the boundary layer grows.