# Control of Corner Separation with Plasma Actuation in a High-Speed Compressor Cascade
## 3 Results
At plane p9, the FV is almost unobservable, while the PV and WV are still dominant flow structures within the high-speed compressor cascade corner separation. The CV exists around the suction surface/endwall corner, but its development is constrained by the PV, thus imposing limited influences on the high-speed compressor cascade flow. At the outlet of the high-speed compressor cascade passage, the flow from the pressure side encounters the corner separation and the TSV is aroused. In summary, when the PV arrives at the suction surface/endwall corner, the high-speed compressor cascade corner separation occurs, and the flow structures of the high-speed compressor cascade corner separation are mainly determined by the development of the PV. Thus suppression of the PV seems key for the control of the high-speed compressor cascade corner separation. On the other hand, the boundary of the high-speed compressor cascade corner separation is mainly determined by the development of the WV, which indicates that the WV plays a crucial role in the interaction between the main flow and the corner separation. Thus suppression of the WV seems another key feature for the control of the high-speed compressor cascade corner separation. According to Figure 5, a high flow loss region can be observed within the high-speed compressor cascade suction surface/endwall corner when the corner separation occurs. While moving downstream, the high flow loss region increases in size and strength with the development of the high-speed compressor cascade corner separation. With the distributions of streamwise vorticity on planes p1-p9, Figure 6 shows the main flow structures within the high-speed compressor cascade corner separation and the development of the corresponding flow loss at the incidence angle of \(-4^{\circ}\). With Figures 5 and 6, it can be found, compared to the case with the incidence angle of \(0^{\circ}\), that the location at which the corner separation occurs is located further away from the blade's leading edge and that the size of the high-speed compressor cascade corner separation is smaller with the incidence angle of \(-4^{\circ}\). Since the size of the high-speed compressor cascade corner separation is smaller with the incidence angle of \(-4^{\circ}\), the corresponding high flow loss region is more constrained to the corner region too. However, the developments of the PV, WV, FV, CV, and TSV, as well as the high flow loss region within the high-speed compressor cascade corner separation in Figure 6, still obey similar rules to those in  
Figure 5: Flow structures within the high-speed compressor cascade corner separation and the development of the corresponding flow loss at an incidence angle of \(0^{\circ}\). (**a**) Flow structures; (**b**) The development of flow loss. Figure 5. According to Figure 5, a high flow loss region can be observed near the blade pressure surface with the incidence angle of \(-4^{\circ}\), and this is caused by the pressure side flow separations at negative incidence angles. With the distributions of streamwise vorticity on planes p1-p9, Figure 7 shows the main flow structures within the high-speed compressor cascade corner separation and the development of the corresponding flow loss at the incidence angle of \(8^{\circ}\). With Figures 5 and 7, it can be found that, with the increase of the incidence angle, the occurrence of the high-speed compressor cascade corner separation becomes closer to the leading edge, and the size of the corner separation increases dramatically too. As a result, the high-speed compressor cascade flow loss is increased simultaneously. However, the developments of the PV, WV, FV, CV, and TSV, as well as the high flow loss region within the high-speed compressor cascade corner separation in Figure 7, still obey similar rules to those in Figures 5 and 6.