On the Lag of Thermometer Exposed in the Air of Variable Temperature and Variable Wind Velocity

Abstract

The equation of heat transfer between the thermometer and the air in which it is exposed is solved graphically, assuming the air temperature and wind velocity fluctuation to be sinusoidal and the thermometer lag coefficient to be inversely proportional to the square root of wind velocity. Two examples are given, one of which is the case of constant air temperature and variable wind velocity, and the other the case, of variable air temperature and variable wind velocity. The influence of wind velocity fluctuation upon the thermometer lag seems to be of negligible order even for large percentages of fluctuation.