Thickness of Boundary Layer Calculator

Boundary Layer Thickness Formula:

\[ \delta = \frac{5.48 \times x}{\sqrt{Re}} \]

Thickness of Boundary Layer (δ):

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is the Boundary Layer Thickness Formula?

The Boundary Layer Thickness formula calculates the thickness of the boundary layer in fluid flow using the distance from the leading edge and the Reynolds number. It provides an estimation of how far from the surface the flow velocity reaches the free-stream velocity.

2. How Does the Calculator Work?

The calculator uses the boundary layer thickness formula:

\[ \delta = \frac{5.48 \times x}{\sqrt{Re}} \]

Where:

\( \delta \) — Thickness of Boundary Layer (m)
\( x \) — Distance Leading Edge for Boundary Layer Flow (m)
\( Re \) — Reynolds Number for Boundary Layer Flow (-)

Explanation: The formula shows that boundary layer thickness increases with distance from the leading edge and decreases with increasing Reynolds number, indicating thinner boundary layers at higher flow velocities or lower viscosities.

3. Importance of Boundary Layer Thickness Calculation

Details: Accurate boundary layer thickness estimation is crucial for analyzing fluid flow characteristics, predicting heat transfer rates, calculating drag forces, and designing efficient aerodynamic and hydrodynamic systems.

4. Using the Calculator

Tips: Enter distance from leading edge in meters and Reynolds number. Both values must be positive numbers. The Reynolds number should be calculated based on the characteristic length and flow conditions.

5. Frequently Asked Questions (FAQ)

Q1: What is the boundary layer in fluid mechanics?
A: The boundary layer is the thin region near a surface where fluid velocity changes from zero at the surface to the free-stream velocity away from the surface.

Q2: Why is the constant 5.48 used in the formula?
A: The constant 5.48 is derived from theoretical and experimental analysis of laminar boundary layer flow over a flat plate and represents the proportionality factor.

Q3: What range of Reynolds numbers is this formula valid for?
A: This formula is typically valid for laminar flow with Reynolds numbers below approximately 5×10⁵, where the flow remains laminar.

Q4: How does boundary layer thickness affect drag?
A: Thicker boundary layers generally result in higher skin friction drag, making boundary layer control important for reducing drag in aerodynamic applications.

Q5: Can this formula be used for turbulent boundary layers?
A: No, this specific formula with constant 5.48 is for laminar boundary layers. Turbulent boundary layers have different growth characteristics and require different formulas.