Large Error in Kinetic Temperature Measurements Due to Position Uncertainty in Particle Tracking Velocimetry

We report on random errors in kinetic temperature measurements due to position uncertainty in particle tracking velocimetry. Using simulated data, we isolate the effects of spatial resolution and the frame rate on particle velocity calculations. A sample of particle velocities is generated from a Gaussian distribution at a known temperature. Particle positions are assigned randomly and roughened to match a prescribed spatial resolution. Velocities are restored using the two-frame tracking method, and the kinetic temperature is calculated. By repeating this procedure, we obtain the discrepancy as a function of the spatial resolution and frame rate. Results show that, under typical experimental conditions, the restored kinetic temperature can deviate significantly from the true value, with spatial resolution playing a more dominant role than the frame rate.