Cj. Bolinder, THE EFFECT OF TORSION ON THE BIFURCATION STRUCTURE OF LAMINAR-FLOW INA HELICAL SQUARE DUCT, Journal of fluids engineering, 117(2), 1995, pp. 242-248
The laminar fully developed flow problem in a helical square duct with
a finite pitch is solved numerically using the finite-volume method w
ith the SIMPLEC algorithm. h(2)-extrapolation is used to locate the li
mit points of the stable solution branches. Results for the friction f
actor are presented. For helical ducts of small pitch, or torsion, it
is verified that all investigated flow properties are very similar to
those for a toroidal duct with the same dimensionless curvature. A new
correlation is proposed for the friction factor ratio.