Page "Wingtip vortices" Paragraph 25

For a typical transport aircraft landing at an airport, these conditions are as follows: We may take and to have values corresponding to the so-called standard conditions, i. e., = 1 atm = 1013. 25 mb = 101325 Pa and = 293. 15 K ( which is 20 ° C = 68 ° F ).

We will take the relative humidity to be a comfortable 35 % ( dew point of 4. 1 ° C = 39. 4 ° F ).

This corresponds to a partial pressure of water vapor of 820 Pa = 8. 2 mb.

We will assume that in a vortex core, the pressure () drops to about 80 % of the ambient pressure, i. e., to about 80 000 Pa.