PREDICTION OF STRONGLY CURVED TURBULENT DUCT FLOWS WITH REYNOLDS STRESS MODEL

The effects of strong convex and concave curvature on turbulent duct f lows are investigated. A compressible Navier-Stokes code incorporating Reynolds stress models has been developed using a four-stage Runge-Ku tta scheme, Numerical computations have been carried out for strongly curved 180-deg turnaround duct hows with a Reynolds stress model, an a lgebraic Reynolds stress model, and a nonlinear k-epsilon model, A det ailed assessment of the models' capability in predicting the effects o f strong streamline curvature has been carried out, It is observed tha t the Reynolds stress model provides the best predictions for major fe atures of this highly curved duct flow, including strong enhancement o f turbulence near the concave wall, complete damping of turbulence nea r the convex wall, and the subsequent separation downstream of the ben d, It is also found that the modeling of the concave curvature effect is different from the modeling of the convex curvature effect, even qu alitatively. The effect of curvature parameter delta/R on the developm ent of mean dow and turbulence has been examined by numerical simulati ons with the Reynolds stress model.