**Author details**

For the staged systems (**Figures 18–21**), it can be seen that many vortices are created at the region localized between the two blades. This region represents the interaction between the highest and the lowest impeller. Hence, the flow becomes more energetic that explain the cause of the development of these vortices. The flow reach the free surface as well as bottom of the tank faster by mounting the flat turbine at the top of the tank. The trailing vortices become more energetic by using the combination between the flat blade at the bottom and the convex blade at the top. The development of the different modes shows that the shoes of the combination is extremely important and can affect the mixing inside the vessel. Consequently, the combination between impellers can lead to affect the final product in terms of homogeneity and the cost in terms of the time mixing and power consumption. This found contradicts what has been observed in the study of the mean velocity field, as it gives almost the same results. In addition, it proves that the mean

The objective of this paper is to investigate experimentally the hydrodynamic structure of the curved blade turbine using the particle image velocimetry. Thereby,

flow is not able to show the real behave of the flow.

**5. Conclusion**

**176**

**Figure 20.**

**Figure 21.**

*POD field for the PDb, PI convex.*

*POD field for the PDb, PI concave.*

*Vortex Dynamics Theories and Applications*

Bilel Ben Amira\*, Mariem Ammar, Ahmad Kaffel, Zied Driss and Mohamed Salah Abid Laboratory of Electromechanical Systems (LASEM), National School of Engineers of Sfax, University of Sfax, Sfax, Tunisia

\*Address all correspondence to: bba.amira7@gmail.com

© 2020 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
