The properly controlled unsteady interactions can reduce the size and intensity of endwall secondary flows, and thus improve the turbine performance.
However, in the open literature there is a limited number of experimental and computational research about the unsteady interactions in such complex configurations.
The results show that unsteady interactions between upstream wake, tip leakage vortex/mixing zone and downstream passage vortex are the main factor affecting turbine endwall secondary flows.
Unsteady interactions can reduce the radial vorticity of turbine endwall secondary flows, and the effects of these interactions on the streamwise vorticity of endwall secondary flows depend on upstream wake characteristics.
Both the levels of unsteady interactions of merging flow structures and the efficiency of the acoustic generation are observed to increase with the merging angles, where the increase in acoustic efficiency can be up to three orders of magnitude.
These results suggest that the unsteady interactions between the turbulent flow and the flame dynamics can be encapsulated in the characteristic stretch rate, which governs the critical flame speed at the mode transitions and thereby plays an important role in determining the stability characteristics of the combustor.
To ensure reliable results the unsteady aerothermoelastic interaction and the radiation have to be taken into account in computational investigations.
However, the simulation of high fidelity unsteady fluid structure interaction using strong coupling algorithms is currently too expensive in order to be useful in industry.
Overall, these numerical results indicate that the proposed algorithm is well suited for the simulation of flows of dense suspensions, flows with high volume-fraction variations or material interfaces, as well as for unsteady fluid solid interaction problems.
