ATMOSPHERIC TURBULENCE MODELING FOR REAL-TIME SIMULATION OF NAP-OF-THE-EARTH (NOE) FLIGHT

SINCE ATMOSPHERIC DISTURBANCES CAN HAVE A LARGE IMPACT ON THE FLYING QUALITIES OF FIXEDAND ROTARY-WING AIRCRAFT, REAL-TIME AIRCRAFT TRAINING AND RESEARCH SIMULATORS MUST INCORPORATE MODELS OF THESE DISTURBANCES THAT ARE APPROPRIATE TO THE VEHICLES AND FLYING TASKS. IN SIMULATING NAP-OF-THE-EARTH (NOE) OPERATIONS IN PARTICULAR, THE DISTURBANCE MODELS SHOULD REPRESENT NONUNIFORM DISTRIBUTIONS IN THE DETERMINISTIC WIND VELOCITY (E.G., WIND SHEARS) AS WELL AS THE STOCHASTIC CHANGES IN THE WIND (E.G., TURBULENCE) OVER THE EXTENT OF THE VEHICLE. THE SPECIFIC PHASE I TECHNICAL OBJECTIVE OF THE WORK PROPOSED HEREIN WILL BE TO DEVELOP A COMPUTATIONAL PROCEDURE FOR SYNTHESIZING A REALISTIC LOW-ALTITUDE ATMOSPHERIC DISTURBANCE MODEL THAT CAN BE USED DURING REAL-TIME ROTORCRAFT SIMULATIONS OF SPECIFIC EXAMPLES OF NOE FLIGHT CONDITIONS. THE MODEL IS INTENDED TO BE USED WITH A COMPLETE ROTORCRAFT MODEL INCORPORATING DISTRIBUTED ROTOR BLADE ELEMENTS AND HOVERING IN OR SLOWLY PASSING THROUGH THE ATMOSPHERIC DISTURBANCES. NONUNIFORM DISTRIBUTIONS OF DETERMINISTIC WIND VELOCITIES AND TURBULENCE CORRELATED WITH SPECIFIC FEATURES OF THE TERRAIN WILL BE REPRESENTED IN THE LOW ALTITUDE ATMOSPHERIC DISTURBANCE MODEL.