Abundant experimental evidence shows that the changes in Reynolds stresses caused by streamline curvature are an order of magnitude larger than would be expected from the explicit curvature-dependent terms appearing in the Reynolds-stress transport equations. Turbulence models developed for simple undistorted shear layers frequently fail to predict this observed changes. In the present work, Bradshaw's one-equation model of turbulence with an algebraic length scale has been used as the base model for turbulence modelling. Two improved schemes have been adopted for turbulent length scale. These are: (1) the algebraic length scale is modified by using the curvature-correction scheme proposed by Bradshaw (1973); (2) a transport equation for the turbulent length scale itself, which is modified by adding an extra curvature-dependent term, is developed to replace the algebraic one.