Thermocouple frequency response compensation leads to convergence of the surface renewal alpha calibration

摘要: Abstract Ramp-like shapes in the turbulent scalar trace are signature of coherent structures, and their characteristics (i.e., amplitude duration) resolved via a structure-function model for use surface renewal flux calculation. The potential to provide inexpensive sensible heat measurements has not been fully realized because this method required calibration against eddy covariance or other more expensive measurement techniques. factor alpha is ideally 0.5, but broad range values have reported literature. Although it hypothesized that sensor size, hence frequency response characteristics, influence alpha, no effort previously made compensate thermocouple signal measurements. We evaluate methods compensating time domain domain, we present novel compensation lag structure function directly). evaluated procedure as affects resolution ramp at both smallest second scales ramp-like shapes. estimates from compensated robust thermocouples (76 μm diameter wire) agree well with fragile (13 μm diameter). Using data collected experiment meta-analysis literature, correct obtain calibrations converge close predicted value 0.5. conclude prevailing on