Blowing wind exerts pressure on the objects that are in its way. The amount of pressure exerted by wind on an object depends on the wind's speed and density, and the object's shape. If you know these three variables, you can easily convert wind speed to pressure in pounds per square inch (psi). Before attempting this calculation, it is useful to know that the density of dry air at sea level is roughly 1.25kg per cubic meter and that every object has a drag coefficient (C) that can be estimated based on its shape.

• Blowing wind exerts pressure on the objects that are in its way.
• Before attempting this calculation, it is useful to know that the density of dry air at sea level is roughly 1.25kg per cubic meter and that every object has a drag coefficient (C) that can be estimated based on its shape.

Write this equation converting wind speed in meters per second (m/s) to pressure in Newton per square meter (N/m^2):

Pressure = 0.5 x C x D x V^2

C = Drag coefficient D = Density of air (kg/m^3) V = Speed of air (m/s) ^ = "to the power of"

Obtain the wind speed value you wish to convert to pressure. It needs to be in meters per second or the equation will not work.

• Obtain the wind speed value you wish to convert to pressure.
• It needs to be in meters per second or the equation will not work.

Example: V = 11m/s

Estimate the drag coefficient based on the shape of the surface of your object that faces the wind.

Example: C for one face of a cubic object = 1.05

Others include:

Sphere: 0.47 Half-Sphere: 0.42 Cone = 0.5 Corner of a Cube = 0.8 Long Cylinder = 0.82 Short Cylinder = 1.15 Streamlined body = 0.04 Streamlined half-body = 0.09

For additional information regarding these shapes, visit the link in the Resources section.