  The formation of the leading-edge vortex (LEV) is a key feature of unsteady
flows past aerodynamic surfaces, but is expensive to model in high fidelity
computations. Low-order methods based on discrete vortex elements are able to
capture the physical behavior of these flows, in particular when enhanced with
a criterion that models the ability of the leading edge to sustain suction.
These models are significantly faster than high order methods, but their
expense still grows as vortex elements are continuously shed and convected into
the wake, in effect an $\mathcal{O}(n^2)$ problem. This work proposes
accelerating the leading-edge suction parameter discrete vortex method (LDVM)
by limiting the number of vortex elements in the LEV coherent structure to N,
hence giving the name to the method N-LEV LDVM. The N-LEV LDVM method correctly
approximates the flows in comparison with the original LDVM model and
computational fluid dynamics (CFD) simulations until the point of LEV
detachment, which N-LEV LDVM is unable to model. We propose reintroducing this
behavior via two physical detachment criteria studied in LEV literature, a
threshold of maximum circulation in the LEV and trailing edge flow reversal. We
demonstrate the ability of the N-LEV LDVM method to accurately predict the
instant in time this detachment occurs for both mechanisms in comparison with
experimental results, laying the ground for their incorporation into the
method.
