Aerodynamic effects of horizontal-temporal variability of air density - A first approach

Abstract

As we know, the lift force and airplane velocity depend on moist (real) air density. Accordingly we discussed the influence of mentioned aerodynamic parameters based on horizontal-temporal changing of air density around their mean values. Using small perturbation of mean air pressure and temperature we determined the horizontal-temporal variability of the air density and airplane velocity as True Airspeed (TAS). The 10% influence of air temperature, air pressure and vapor pressure involve about 2.4%, 0.8% and 0.05% air density variability, respectively. The same 10% decreasing in air temperature causes 1.2% positive changing in assumed mean TAS. The short-term variability of moist air density has also been investigated and our results show 3–4% changing in TAS during a strong cold front crossing. On the other hand the climatic variability of atmospheric state variables much higher than 10% thus the long-term (climatic) variation of real atmospheric air density (and TAS of course) has to be very significant variability in time!