Single-component force balance for the measurement of low-magnitude mean aerodynamic loads

A novel force balance is developed for the measurement of low-magnitude mean aerodynamic forces. The measurement of such small loads is often desired for low Reynolds number wind tunnel experiments, however commercially available options for force measurement do not have high enough sensitivity or accuracy. A force balance is designed to measure forces that range from mN to hundreds of milli-Newtons in magnitude. The sensitivity of the balance is derived theoretically, and the actual value is determined from calibration. The force balance demonstrates both a high degree of linearity, and low hysteresis over the desired load range. The measurement capability of the force balance is validated using measurements of the drag force on a circular cylinder, and the lift force on a square cylinder for Reynolds numbers between 1100 and 10 000. In each case, the force measured by the newly developed force balance shows good agreement with data from literature, and a level of accuracy currently not possible with commercially available sensors for such low-magnitude loads.