NUMERICAL SIMULATIONS OF COMMERCIAL AIRCRAFT WAKES SUBJECTED TO AIRPORT SURFACE WEATHER CONDITIONS

Using tower flyby data for validation, we have developed a two-dimensi onal numerical simulation of the influence or surface weather conditio ns on wake vortex motion and decay for representative commercial aircr aft. Our simulations support the conjecture that the ratio of eddy vis cosity to kinematic viscosity, appropriate for modeling aircraft, wake s, scales linearly with circulation, which yields a nominally constant equivalent Renolds number For all commercial aircraft sizes, We have tested the constant eddy. viscosity approximation for three different aircraft types and six surface weather states, showing the utility of the approach in predicting wake vortex motion and decay, Subsequently, we have shown how data from one aircraft flight test can be used to i nfer the decay behavior of another, and we have examined the influence of the six surface weather stairs on the vortex decay behavior predic ted for a large commercial aircraft, Based upon these simulations, we have determined that the two-dimensional, constant eddy viscosity appr oach can be useful in assessing the influence of surface weather condi tions on wake vortex decay.