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The hydrodynamic boundary layer thickness is the distance from a solid surface where the fluid velocity reaches 99% of the free-stream velocity. It represents the region affected by viscous forces in fluid flow over a surface.
The calculator uses the formula:
Where:
Explanation: The displacement thickness represents how much the boundary layer has displaced the main flow, and this simple relationship provides the hydrodynamic boundary layer thickness based on that displacement.
Details: Boundary layer calculations are crucial in fluid dynamics for understanding drag forces, heat transfer, and flow separation in various engineering applications including aerodynamics, hydrodynamics, and HVAC systems.
Tips: Enter the displacement thickness in meters. The value must be positive and valid for accurate calculation of the hydrodynamic boundary layer thickness.
Q1: What is the physical significance of displacement thickness?
A: Displacement thickness represents the distance by which the external streamlines are shifted outward due to the formation of the boundary layer.
Q2: Is this relationship valid for all flow conditions?
A: This specific relationship (δ_h = 8×δ_d) is typically valid for laminar boundary layers over flat plates with zero pressure gradient.
Q3: How does turbulence affect boundary layer thickness?
A: Turbulent boundary layers are typically thicker than laminar ones and have different velocity profiles, which would require different relationships.
Q4: What are typical values for boundary layer thickness?
A: Boundary layer thickness varies significantly with flow conditions, ranging from millimeters in laboratory settings to meters in atmospheric boundary layers.
Q5: Can this calculator be used for compressible flows?
A: This simple relationship is primarily for incompressible flows. Compressible flows require more complex calculations accounting for density variations.