In the present work, high resolution CFD simulations have been performed on an idealised
problem of the interaction of an independently generated vortex with a rotor blade, including
a case where the vortex directly impacts on the blade. The resulting blade pressures and
acoustics are comprehensively compared against experimental measurements. Two different
modelling approaches are used: the first is to impose the vortex as a perturbation to the velocity
field, and the second is to fully resolve the vortex formation, evolution and its interaction
with the blade. For a case in which the vortex passes near the blade surface, the the fully resolved
approach is confirmed to accurately preserve the vortex structure. The far field acoustic
predictions offered by the fully resolved approach are seen to be very accurate and definite
improvements are observed in the computed blade pressures and acoustics over the imposed
vortex approach and other similar works in the literature. For a case in which the vortex axis
passes through the blade, the shape and width of the acoustic pulse in the far field is accurately
represented by the fully resolved approach, while the magnitude is slightly underpredicted.
The improvement in prediction offered by the fully resolved approach is because this method
allows for a more realistic representation of phenomena, such as dynamic change in vortex
structure and trajectory due to the blade passage, that become important when the vortex
miss-distance becomes small
