The trailing vortex, also known, smewhat erroneously, as the 'wingtip vortex', is created due to the pressure differentials between the upper and lower sides of an aircraft wing. The resultant vorticity 'coils up' to form distinct trailin vortices, trailing from the wingtips. The assumption of perfect line-vortex systems from the wingtips is inherent in the horseshoe vortex model.

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