When poiseuille flow occurs in an open-tubular curved pipe, the secondary currents created by centrifugal forces within the primary current cause a lowering of the HETP of the primary current for samples carried along. An expression is developed for th e first approximation of this effect,which is represented by a term proportional to the fourth power of the primary flow. The calculations are made for the less involved case of a circular pipe with retentionless walls, and serve to show that, while measurable effects can be expected for relatively high flow-rates, the effect is negligible in the case of the relatively slow flows of liquids at which optimal chromatographic separations are obtained. © 1979.
