PREDICTION OF 3-DIMENSIONAL DEVELOPING TURBULENT-FLOW IN A SQUARE DUCT WITH AN ANISOTROPIC LOW-REYNOLDS-NUMBER KAPPA-EPSILON MODEL

Three-dimensional developing turbulent flow in a square duct involving turbulence-driven secondary motion is numerically predicted with an anisotropic low-Reynolds-number k-epsilon turbulence model. Special attention has been given to both regions close to the wall and the corner, which are known to influence the characteristics of secondary flow a great deal. Hence, the no-slip boundary condition at the wall is directly used in place of the common wall function approach. The resulting set of equations simplified only by the boundary layer assumption are first compared with previous algebraic stress models, and solved with a forward marching numerical procedure for three-dimensional shear layers. Typical predicted quantities such as mean axial and secondary velocities, friction coefficients, turbulent kinetic energy, and Reynolds shear stress are compared with available experimental data. These results indicate that the present anisotropic k-epsilon turbulence model performs quite well for this complex flow field.