Numerical Investigation of Blade Erosion in Helicopter Brownout

The occurrence of helicopter brownout poses a significant risk to pilots and leads to blade erosion. An approach for simulating blade erosion in helicopter brownout is subsequently developed by coupling models of helicopter brownout, rotor blade erosion, and collision. The erosion rates of a plane with different impact velocities, impact angles, and materials, including stainless steel, nickel, titanium, glass-fiber-reinforced epoxy, bidirectional carbon-fiber-reinforced epoxy, and polyurethane, are applied and compared with experimental data. The blade erosion of EH-60L in brownout under the taxi-pass case is then analyzed, and the effects of airspeed and flight height on the blade erosion are also studied. It shows that the predicted variations in blade erosion rate are found to match very well with the experimental data. As time progresses, the collision between the sand cloud and the rotor blade, the blade erosion, and the erosion zone become significantly more pronounced. Erosion at the blade tip is larger than that at the inner blade due to the longer time period and larger impact velocity and angle. Moreover, the erosion occurring at the blade tip and the erosion zone initially increase and then decrease with the helicopter airspeed, while they diminish with increasing flight height.