A mixing length approach is applied to the case of a spiral flow, where pressure flow acts across a Couette flow as in the case of end leakage around a shaft. The mixing length is expressed as a dimensionless function of the modulus of the local velocity vector, drawing upon an empirical relationship based upon wall-law flow data. Results are shown to be in approximate agreement with a set of experimental measurements. This indicates that the computation scheme accounts for the major factors in such flows, where the shear stress chances direction outward from a wall.Contributed to ASLE by the authors.