Comparison and numerical and experimental study of flow patterns in sharp bends

Study of flow pattern in sharp bends is so important because of the complexity of the flow pattern in this bends in to mild bends. In this study, the numerical study of flow pattern in three sharp bends 90°, 120° and 180° have been done. Corresponding numerical model is based on the Fluent software with free surface model. And the k  (RNG) turbulence model is used to simulate turbulent flow parameters. The results show that the overall pattern of velocity distribution for the three bends have been studied are identical. In this bends, maximum velocity until around the end of the bend is located in the inner wall and is transmitted to the outer wall in the sections located after the bend. Study area tends to flow separation in the inner wall in the ending section of the bend indicates that by increasing the angle of curvature of the bend, bending effect on the tendency to flow separation within the channel width is increase. The shear stress distribution pattern at each three bend is identical and similar to the velocity pattern.

Keywords:

sharp bends , numerical model , velocity distribution , flow separation , shear stress distribution