Numerical modeling of turbulent flow in curved channels of compound cross-section

A mathematical model based on orthogonal curvilinear coordinate system is developed which applies several algebraic stress models to simulate secondary currents in helically coiled channels. The model is validated using measurements in curved open channels with a simple rectangular cross-section. Secondary flows driven by both the centrifugal force and turbulence stresses were reproduced using LY and NR algebraic stress models, and SY nonlinear k–ε model. Impacts on secondary motion by variations in cross-section and channel curvature configurations have been discussed and the relationship between secondary flow pattern and different driving forces is analyzed. Predicted secondary currents in compound curved channels have been compared with published straight channel measurements on a qualitative basis.