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Friction Velocity, also called shear velocity, is a form by which a shear stress may be re-written in units of velocity. It represents the velocity scale that characterizes turbulent flow near a boundary surface.
The calculator uses the formula:
Where:
Explanation: This formula calculates friction velocity based on boundary layer height, Coriolis frequency, and a dimensionless constant that varies depending on atmospheric conditions.
Details: Friction velocity is crucial in meteorology and fluid dynamics for understanding turbulent flows, boundary layer dynamics, and surface-atmosphere interactions. It helps in predicting weather patterns, air pollution dispersion, and ocean current behavior.
Tips: Enter boundary layer height in meters, Coriolis frequency in radians per second, and the dimensionless constant. All values must be positive numbers.
Q1: What is the typical range of friction velocity values?
A: Friction velocity typically ranges from 0.1 to 1.0 m/s in atmospheric boundary layers, depending on surface roughness and wind speed.
Q2: How does Coriolis frequency vary with latitude?
A: Coriolis frequency increases with latitude, being zero at the equator and maximum at the poles. It is calculated as f = 2Ωsin(φ), where Ω is Earth's rotation rate and φ is latitude.
Q3: What factors influence the dimensionless constant λ?
A: The dimensionless constant depends on atmospheric stability, surface roughness, and the specific boundary layer model being used. Typical values range from 0.1 to 1.0.
Q4: Why is this formula specific to non-equatorial regions?
A: The formula assumes significant Coriolis effects, which are minimal near the equator where f approaches zero. Different formulations are needed for equatorial regions.
Q5: What are the main applications of friction velocity calculations?
A: Applications include weather forecasting, climate modeling, air quality monitoring, wind energy assessment, and ocean current prediction.