Local Friction Coefficient Given Local Reynolds Number Calculator

Formula Used:

\[ \text{Local Friction Coefficient} = 2 \times 0.332 \times (\text{Local Reynolds Number})^{-0.5} \]

Local Friction Coefficient (Cfx):

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is Local Friction Coefficient?

The Local Friction Coefficient for flow in ducts is the ratio of wall shearing stress to the dynamic head of the stream. It quantifies the resistance to flow at a specific point along the duct surface.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ \text{Local Friction Coefficient} = 2 \times 0.332 \times (\text{Local Reynolds Number})^{-0.5} \]

Where:

Local Reynolds Number — The ratio of inertial forces to viscous forces at a specific location
0.332 — Empirical constant derived from boundary layer theory
2 — Factor accounting for both sides of the flow
-0.5 — Exponent indicating inverse square root relationship

Explanation: This formula is derived from Blasius solution for laminar boundary layer flow over a flat plate, providing the local skin friction coefficient.

3. Importance of Local Friction Coefficient Calculation

Details: Accurate calculation of local friction coefficient is crucial for predicting pressure drops, designing efficient duct systems, and analyzing fluid flow characteristics in various engineering applications.

4. Using the Calculator

Tips: Enter the Local Reynolds Number (must be greater than 0). The calculator will compute the corresponding Local Friction Coefficient using the established formula.

5. Frequently Asked Questions (FAQ)

Q1: What range of Reynolds numbers is this formula valid for?
A: This formula is specifically valid for laminar flow conditions, typically for Reynolds numbers below 5×10⁵.

Q2: How does local friction coefficient differ from average friction coefficient?
A: Local friction coefficient gives the value at a specific point, while average friction coefficient provides the mean value over a length of the surface.

Q3: Can this formula be used for turbulent flow?
A: No, this formula is derived for laminar flow conditions. Different correlations exist for turbulent flow regimes.

Q4: What are typical values of local friction coefficient?
A: Values typically range from 0.001 to 0.01 for most engineering applications, decreasing with increasing Reynolds number.

Q5: How does surface roughness affect the local friction coefficient?
A: Surface roughness significantly increases friction coefficient in turbulent flow, but has minimal effect in laminar flow where this formula applies.