## 6 Conclusions  
In this study, a dual volute turbocharger turbine was investigated. The turbine performance reduces with increasing the inequality of the inlet pressure of the volute limbs. Isolating was applied to reduce the interaction of the entries in the interspace region. The results show that:  
* Separating the rotor sectors in the interspace region near the tongues leads to an efficiency drop because of preventing the flow from rotating and entering with favorable incidence to the rotor, and because of reducing the effective area of the two stator vanes in the isolating area; however, isolating helps to decrease the dissipation of momentum in the mixing loss, and a higher MFR leads to a higher efficiency gain. This efficiency gain can compensate the pre-mentioned generated entropy in partial case, but not in the other unequal cases.  
Then, the non-uniform inlet flow to the rotor in the equal and partial admission cases was investigated to find the effectiveness of the pressure level and gradient on the extent, intensity, and central location of vortices in the passages, and these results were obtained:  
* With the decreasing pressure level, the center of the tip vortex shifted to the previous sections.
* The P.s pressure level affects the tip vortex more than the S.s pressure.
* The intensity of the tip vortex core is more affected by pressure level than the SPR.
* The SPR is more effective in the wide-spreading of the tip vortex than the pressure level and higher inequality (SPR-1), resulting in a more expanded but weaker tip vortex. In equal admission, when SPR changed 2% from unity, the maximum of vorticity intensity at the center of the tip vortex decreased by 10%.
* SPR does not have any impact on the LR vortex, and only the pressure level affects the vortices' strength and the location of the vortex center. In equal admission, when the SPR changed 2% from the unity, the vorticity width did not change; also, with an 8% drop in the pressure level, the maximum of vorticity intensity at the LR vortex core decreased by 23%.
* The LR vortex center moves to the right-hand side with the increasing pressure level.
* The P.s pressure level affects the Tr. vortex more than the S.s pressure level. When the pressure level increased by 8%, the maximum of vorticity intensity at the center of the right head of the Tr. vortex, which is closer to the P.s, rises about 19%, but the left-hand side of this vortex, which is closer to the S.s, grows 12%.
* Considering the passages in the partial case shows that with sufficiently decreasing pressure, the left-hand side of the Tr. vortex almost disappears, but the right-hand side is affected less.
* Rising the pressure of each passage side enhances the vorticity of the other Tr. vortex's head side.
* The Tr. vortex is located at the trailing edge, which caused a sharp growth in the radial velocity there, but also caused a decline in the axial and circumferential components of the velocity.
* In the LR vortex, the circumferential velocity increases sharply, but the radial velocity decreases strongly, and the axial velocity is not affected significantly.
* In the tip vortex, circumferential velocity increases hugely, axial velocity drops significantly, and radial velocity increases slightly.  
A.S. made the geometry model. The research has done by supervision of M.H.S.F., A.K. and A.S. carried out the simulations, methodology and the analysis. A.S. and A.K. wrote and refined the paper. All authors have read and approved the final manuscript.  
This research received no external funding.  
The authors declare no conflict of interest.