Abstract: In this paper, investigations on a RNG based algebraic transport turbulentmodel is carried out.Aproper way proposed here to choose a suitable root for the eddyviscosity from solutions of a cubic equation derived from the renormalization group theoryhas resonable physical meaning. In addition, two-peak average method is used to determinethe thickness of boundary layers inside separation regions,which has improved the way ofBaldwin-Lomax algebraic turbulence model and can be applied in engineering calculation...