DescriptionWe illustrate how the diffusion of vorticity from the boundary layer into the bulk flow can be modelled using a single point vortex. Existing studies that use impulse theory to calculate the fluid forces on a body do not account for the viscous diffusion of vorticity because it is unnecessary for their specific flow conditions or research aims. However, this means that existing models are only valid where advection of vorticity dominates, making them unsuitable for use during the initial period in which the body starts to move or at low Reynolds numbers. In this work, we show how models based on impulse theory can also account for the viscous diffusion of vorticity by encapsulating it in a single point vortex, the speed of which can be analytically calculated. Consequently, we show how impulse theory, already successfully used at high Reynolds numbers, can also be applied at low Reynolds numbers and smaller timescales, where the viscous diffusion of vorticity is significant.
|24 Nov 2020
|School of Mathematical & Computer Sciences
|Degree of Recognition