Alternative Method of Wind Measurement via Interpreting Dynamic Behaviors of a Helium Balloon

Abstract

Wind measurement is crucial for wind energy assessment and development of wind farms. For conventional measurement, wind sensors are implemented on a wind mast at desired heights. This approach causes substantial costs of construction, time, and maintenance. The paper presents a simple lowcost method of wind measurement via interpreting dynamic behaviors of a helium balloon. A helium balloon is installed at the desired height where it is pulled by a cord of corresponding length. The end of the cord is tied to a specially designed holding mechanism of a rotating arm, which always leads to direction of wind. For wind speed, aerodynamic performance of the helium balloon is numerically investigated by mathematical models. It is found that drag force due to wind through the helium balloon dynamically balances forces of buoyancy, gravity, and tension. Therefore, wind speed at the balloon height can be determined from motion equations and drag equation since variables of the helium balloon are measured such as the swing angle away from vertical line and cord tension. By applying the wind profile power law, the wind speed data at the balloon height can be further adjusted to the values at the desired height. Experiments in a field study are readily performed to show great viability of the proposed methodology.