A hydrodynamic model of aircraft vortex wakes in an irregular wind shear field near the ground is developed and used as a basis for modeling the characteristics of a laser doppler detection and vortex location system. The trailing vortex sheet and the wind shear are represented by discrete free vortices distributed over a two-dimensional grid. The time dependent hydro-dynamic equations are solved by direct numerical integration in the Boussinesq approximation. The ground boundary is simulated by images, and fast Fourier Transform techniques are used to evaluate the vorticity stream function. The atmospheric turbulence was simulated by constructing specific realiza¬tions at time t=0, assuming Kolmogoroff’s law applies, and that the dissipation rate is constant throughout the flow field. Although the primary purpose of the study reported here was to analyze the laser doppler velocimeter system, characteristics of other systems are also discussed in the framework of the present model.
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