Empirical Equations for Wind Induced Turbulence

The main parameter affecting gas transfer in a purely wind-driven regime is the shear stress due to the wind field, given by the friction velocity u*a in the air flow over the water surface. This is related to the wind velocity U10 at the standard 10 m level, u*a = yCb U10. CD is the quadratic law drag coefficient, CD = (0.8 + 0.065 U10) x 10-3, representing an increasing roughness effect due to wave growth with increasing wind speed.

As summarized by Chu and Jirka, for low wind speeds, a linear relationship,

and for high wind speeds, a quadratic relationship,

with Kl in mday-1 and u*a in cms-1, represents a good approximation to data, coming mostly from laboratory experiments. Donelan and Wanninkhoff summarize some field data for large-scale ocean measurements for which the wind fields are usually highly variable, both in space and time.

Renewable Energy 101

Renewable Energy 101

Renewable energy is energy that is generated from sunlight, rain, tides, geothermal heat and wind. These sources are naturally and constantly replenished, which is why they are deemed as renewable. The usage of renewable energy sources is very important when considering the sustainability of the existing energy usage of the world. While there is currently an abundance of non-renewable energy sources, such as nuclear fuels, these energy sources are depleting. In addition to being a non-renewable supply, the non-renewable energy sources release emissions into the air, which has an adverse effect on the environment.

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