Uncertainty Quantification of Flow Uniformity Measurements in a Slotted Wall Wind Tunnel

Flow Angularity Investigations in an Automotive Slotted Wall Wind Tunnel

“…Furthermore, since the overall flow interference from the old commissioning strut was larger than for the new flow measurement rig due to a thicker structure and a shorter standoff distance between the probes and the leading edge of the vertical strut, it is concluded that the present data is more likely to be representative of the actual flow pattern. This is further strengthened by the fact that the present measurements are corrected for rig interference [24], which was not the case for the commissioning measurements.…”

“…Typical uncertainties for the flow angularity measurements are given in Table 1, where it can be seen that the uncertainties varied slightly over a plane, but had a weak velocity dependency. This is since the uncertainties are not dominated by the pressure measurements, but rather by the optical measurement of the offset angles of the probe arms [24]. Furthermore, it can be noted that the measurement uncertainties for the full measurement chain were significantly lower than the stated accuracy of a factory calibrated Air data probe (±0.15 • ).…”

“…The total uncertainty of the full measurement chain was estimated according to the JCGM Guide to the expression of uncertainty in measurement [23], and included the uncertainty of all measured quantities and the interference correction. A more thorough description of the rig, the interference correction, and the quantification of measurement uncertainties was given by Ljungskog et al [24]. Typical uncertainties for the flow angularity measurements are given in Table 1, where it can be seen that the uncertainties varied slightly over a plane, but had a weak velocity dependency.…”

“…Uncertainty distribution as one standard deviation over a full measurement plane for pitch (α) and yaw (β)[24].…”