Friction Velocity given Wind Speed at Height above Surface Calculator

✖Von Kármán Constant is often used in turbulence modeling, for instance in boundary-layer meteorology to calculate fluxes of momentum, heat and moisture from the atmosphere to the land surface.ⓘ Von Kármán Constant [k]			+10% -10%
✖Wind Speed is a fundamental atmospheric quantity caused by air moving from high to low pressure, usually due to changes in temperature.ⓘ Wind Speed [U]			+10% -10%
✖Height z above Surface where the Wind Speed is measured.ⓘ Height z above Surface [Z]			+10% -10%
✖Roughness Height of Surface is the height of the roughness of the surface.ⓘ Roughness Height of Surface [z₀]			+10% -10%

✖Friction Velocity, also called shear velocity, is a form by which a shear stress may be re-written in units of velocity.ⓘ Friction Velocity given Wind Speed at Height above Surface [V_f]

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Friction Velocity given Wind Speed at Height above Surface Solution

STEP 0: Pre-Calculation Summary

Formula Used

Friction Velocity = Von Kármán Constant*(Wind Speed/(ln(Height z above Surface/Roughness Height of Surface)))
V_f = k*(U/(ln(Z/z₀)))
This formula uses 1 Functions, 5 Variables

Functions Used

ln - The natural logarithm, also known as the logarithm to the base e, is the inverse function of the natural exponential function., ln(Number)

Variables Used

Friction Velocity - (Measured in Meter per Second) - Friction Velocity, also called shear velocity, is a form by which a shear stress may be re-written in units of velocity.
Von Kármán Constant - Von Kármán Constant is often used in turbulence modeling, for instance in boundary-layer meteorology to calculate fluxes of momentum, heat and moisture from the atmosphere to the land surface.
Wind Speed - (Measured in Meter per Second) - Wind Speed is a fundamental atmospheric quantity caused by air moving from high to low pressure, usually due to changes in temperature.
Height z above Surface - (Measured in Meter) - Height z above Surface where the Wind Speed is measured.
Roughness Height of Surface - (Measured in Meter) - Roughness Height of Surface is the height of the roughness of the surface.

STEP 1: Convert Input(s) to Base Unit

Von Kármán Constant: 0.4 --> No Conversion Required
Wind Speed: 4 Meter per Second --> 4 Meter per Second No Conversion Required
Height z above Surface: 8 Meter --> 8 Meter No Conversion Required
Roughness Height of Surface: 6.1 Meter --> 6.1 Meter No Conversion Required

STEP 2: Evaluate Formula

Substituting Input Values in Formula

V_f = k*(U/(ln(Z/z₀))) --> 0.4*(4/(ln(8/6.1)))

Evaluating ... ...

V_f = 5.90073262775913

STEP 3: Convert Result to Output's Unit

5.90073262775913 Meter per Second --> No Conversion Required

FINAL ANSWER

5.90073262775913 ≈ 5.900733 Meter per Second <-- Friction Velocity

(Calculation completed in 00.007 seconds)

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< Estimating Marine and Coastal Winds Calculators

Wind Speed at Height z above Surface

LaTeX Go Wind Speed = (Friction Velocity/Von Kármán Constant)*ln(Height z above Surface/Roughness Height of Surface)

Wind Speed at Height z above Surface given Standard Reference Wind Speed

LaTeX Go Wind Speed = Wind Speed at Height of 10 m/(10/Height z above Surface)^(1/7)

Wind Speed at Standard 10-m Reference Level

LaTeX Go Wind Speed at Height of 10 m = Wind Speed*(10/Height z above Surface)^(1/7)

Height z above Surface given Standard Reference Wind Speed

LaTeX Go Height z above Surface = 10/(Wind Speed at Height of 10 m/Wind Speed)^7

Friction Velocity given Wind Speed at Height above Surface Formula

LaTeX Go

Friction Velocity = Von Kármán Constant*(Wind Speed/(ln(Height z above Surface/Roughness Height of Surface)))
V_f = k*(U/(ln(Z/z₀)))

What is Friction Velocity?

Shear velocity, also called friction velocity, is a form by which shear stress may be rewritten in units of velocity. It is useful as a method in fluid mechanics to compare true velocities, such as the velocity of a flow in a stream, to a velocity that relates shear between layers of flow.

What is 10m Wind?

Surface wind is the wind blowing near the Earth's surface. The wind 10m chart displays the modelled average wind vector 10 m above the ground for every grid point of the model (ca. every 80 km). Generally, the actually observed wind velocity at 10 m above ground is a little bit lower than the modelled one.

How to Calculate Friction Velocity given Wind Speed at Height above Surface?

Friction Velocity given Wind Speed at Height above Surface calculator uses Friction Velocity = Von Kármán Constant*(Wind Speed/(ln(Height z above Surface/Roughness Height of Surface))) to calculate the Friction Velocity, The Friction Velocity given Wind Speed at Height above Surface formula is defined as a form by which a shear stress may be re-written in units of velocity. Friction Velocity is denoted by V_f symbol.

How to calculate Friction Velocity given Wind Speed at Height above Surface using this online calculator? To use this online calculator for Friction Velocity given Wind Speed at Height above Surface, enter Von Kármán Constant (k), Wind Speed (U), Height z above Surface (Z) & Roughness Height of Surface (z₀) and hit the calculate button. Here is how the Friction Velocity given Wind Speed at Height above Surface calculation can be explained with given input values -> 5.900733 = 0.4*(4/(ln(8/6.1))).

FAQ

What is Friction Velocity given Wind Speed at Height above Surface?

The Friction Velocity given Wind Speed at Height above Surface formula is defined as a form by which a shear stress may be re-written in units of velocity and is represented as V_f = k*(U/(ln(Z/z₀))) or Friction Velocity = Von Kármán Constant*(Wind Speed/(ln(Height z above Surface/Roughness Height of Surface))). Von Kármán Constant is often used in turbulence modeling, for instance in boundary-layer meteorology to calculate fluxes of momentum, heat and moisture from the atmosphere to the land surface, Wind Speed is a fundamental atmospheric quantity caused by air moving from high to low pressure, usually due to changes in temperature, Height z above Surface where the Wind Speed is measured & Roughness Height of Surface is the height of the roughness of the surface.

How to calculate Friction Velocity given Wind Speed at Height above Surface?

The Friction Velocity given Wind Speed at Height above Surface formula is defined as a form by which a shear stress may be re-written in units of velocity is calculated using Friction Velocity = Von Kármán Constant*(Wind Speed/(ln(Height z above Surface/Roughness Height of Surface))). To calculate Friction Velocity given Wind Speed at Height above Surface, you need Von Kármán Constant (k), Wind Speed (U), Height z above Surface (Z) & Roughness Height of Surface (z₀). With our tool, you need to enter the respective value for Von Kármán Constant, Wind Speed, Height z above Surface & Roughness Height of Surface and hit the calculate button. You can also select the units (if any) for Input(s) and the Output as well.

How many ways are there to calculate Friction Velocity?

In this formula, Friction Velocity uses Von Kármán Constant, Wind Speed, Height z above Surface & Roughness Height of Surface. We can use 3 other way(s) to calculate the same, which is/are as follows -

Friction Velocity = sqrt(Wind Stress/(Density of Air/Water Density))
Friction Velocity = (Height of Boundary Layer*Coriolis Frequency)/Dimensionless Constant
Friction Velocity = 0.0275*Geostrophic Wind Speed

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