Author Contributions
Conceptualization, S.Z. and Z.L.; formal analysis, S.Z. and Z.L.; funding acquisition, J.L.; investigation, S.Z., Z.G., and S.M.; methodology, S.Z., J.L., and L.Z.; project administration, J.L.; resources, J.L.; software, L.Z. and D.P.; supervision, J.L. and L.Z.; validation, S.Z.; writing—original draft, S.Z.; writing—review and editing, L.Z. All authors have read and agreed to the published version of the manuscript.
Figure 1.
Geometry of wing leading edge.
Figure 1.
Geometry of wing leading edge.
Figure 2.
Geometrical models of the secondary flow systems: (a) ram-air secondary flow system, (b) submerged secondary flow system (length unit is mm).
Figure 2.
Geometrical models of the secondary flow systems: (a) ram-air secondary flow system, (b) submerged secondary flow system (length unit is mm).
Figure 3.
The area distribution of secondary flow systems.
Figure 3.
The area distribution of secondary flow systems.
Figure 4.
Parameters of the centerline.
Figure 4.
Parameters of the centerline.
Figure 5.
Schematic diagram of the cylindrical tube and the monitoring surface.
Figure 5.
Schematic diagram of the cylindrical tube and the monitoring surface.
Figure 6.
Test models of secondary flow systems installation on the wind tunnel test section: (a) ram-air secondary flow system, (b) submerged secondary flow system, (c) test model installation on the wind tunnel test section.
Figure 6.
Test models of secondary flow systems installation on the wind tunnel test section: (a) ram-air secondary flow system, (b) submerged secondary flow system, (c) test model installation on the wind tunnel test section.
Figure 7.
Locations of measuring points at the total pressure rake.
Figure 7.
Locations of measuring points at the total pressure rake.
Figure 8.
Calculating mesh and boundary conditions.
Figure 8.
Calculating mesh and boundary conditions.
Figure 9.
Comparison of experimental and simulation total pressure recovery: (a) ram-air secondary flow system, (b) submerged secondary flow system.
Figure 9.
Comparison of experimental and simulation total pressure recovery: (a) ram-air secondary flow system, (b) submerged secondary flow system.
Figure 10.
Comparison of experimental and simulation total pressure distortion coefficients: (a) ram-air secondary flow system, (b) submerged secondary flow system.
Figure 10.
Comparison of experimental and simulation total pressure distortion coefficients: (a) ram-air secondary flow system, (b) submerged secondary flow system.
Figure 11.
Pressure coefficient distributions on the wing surface of the ram-air secondary flow systems at (a) Mach number 0.4, (b) Mach number 0.8, (c) Mach number 1.1, (d) Mach number 1.5, (e) Mach number 2.0.
Figure 11.
Pressure coefficient distributions on the wing surface of the ram-air secondary flow systems at (a) Mach number 0.4, (b) Mach number 0.8, (c) Mach number 1.1, (d) Mach number 1.5, (e) Mach number 2.0.
Figure 12.
Intake streamlines of the ram-air secondary flow system.
Figure 12.
Intake streamlines of the ram-air secondary flow system.
Figure 13.
Schematic illustration of the analyzed cross-sections in the tube of the ram-air secondary flow system (named Slice 1, Slice 2, etc.).
Figure 13.
Schematic illustration of the analyzed cross-sections in the tube of the ram-air secondary flow system (named Slice 1, Slice 2, etc.).
Figure 14.
The curve of pressure changes along the tube of the ram-air secondary flow system.
Figure 14.
The curve of pressure changes along the tube of the ram-air secondary flow system.
Figure 15.
The streamlines inside the tube and the total pressure recovery distributions of nine flow field Slices in the ram-air secondary flow tube at (a) Mach number 0.4, (b) Mach number 0.8, (c) Mach number 1.1, (d) Mach number 1.5, (e) Mach number 2.0.
Figure 15.
The streamlines inside the tube and the total pressure recovery distributions of nine flow field Slices in the ram-air secondary flow tube at (a) Mach number 0.4, (b) Mach number 0.8, (c) Mach number 1.1, (d) Mach number 1.5, (e) Mach number 2.0.
Figure 16.
Pressure coefficient distribution on the wing surfaces of the submerged secondary flow system at (a) Mach number 0.4, (b) Mach number 0.8, (c) Mach number 1.1, (d) Mach number 1.5, (e) Mach number 2.0.
Figure 16.
Pressure coefficient distribution on the wing surfaces of the submerged secondary flow system at (a) Mach number 0.4, (b) Mach number 0.8, (c) Mach number 1.1, (d) Mach number 1.5, (e) Mach number 2.0.
Figure 17.
Flow streamlines at the intake of the submerged secondary flow system: (a) vertical z-axis direction view, (b) isometric view.
Figure 17.
Flow streamlines at the intake of the submerged secondary flow system: (a) vertical z-axis direction view, (b) isometric view.
Figure 18.
Schematic illustration of the analyzed cross-sections in the tube of the submerged secondary flow system (named Slice 1, Slice 2, etc.).
Figure 18.
Schematic illustration of the analyzed cross-sections in the tube of the submerged secondary flow system (named Slice 1, Slice 2, etc.).
Figure 19.
The curve of pressure changes along the tube of the submerged secondary flow system.
Figure 19.
The curve of pressure changes along the tube of the submerged secondary flow system.
Figure 20.
The streamlines inside the tube and the total pressure recovery distributions of nine flow field Slices in the submerged secondary flow tube at (a) Mach number 0.4, (b) Mach number 0.8, (c) Mach number 1.1, (d) Mach number 1.5, (e) Mach number 2.0.
Figure 20.
The streamlines inside the tube and the total pressure recovery distributions of nine flow field Slices in the submerged secondary flow tube at (a) Mach number 0.4, (b) Mach number 0.8, (c) Mach number 1.1, (d) Mach number 1.5, (e) Mach number 2.0.
Table 1.
Wind tunnel test conditions.
Table 1.
Wind tunnel test conditions.
Experimental Conditions | Mach Number | Total Temperature/K | Total Pressure/Pa |
---|
1 | 0.4 | 297.37 | 104,517 |
2 | 0.8 | 325.03 | 114,824 |
3 | 1.1 | 357.89 | 129,843 |
4 | 1.5 | 417.82 | 177,629 |
5 | 2.0 | 518.67 | 209,392 |
Table 2.
The relative positions of the measurement points.
Table 2.
The relative positions of the measurement points.
Measurement Points Circle Serial Number | Distance from Center of Circle ri (mm) | Relative Distance from the Center of Circle ri/R |
---|
1 | 10.033 | 0.316 |
2 | 17.399 | 0.548 |
3 | 22.447 | 0.707 |
4 | 26.575 | 0.837 |
5 | 30.131 | 0.949 |
Table 3.
Calculation results of four grids.
Table 3.
Calculation results of four grids.
| Mesh Cells (Million) |
|
|
---|
Grid 1 | 0.9 | 0.7043 | 0.054 |
Grid 2 | 1.8 | 0.6935 | 0.032 |
Grid 3 | 3.6 | 0.6924 | 0.033 |
Grid 4 | 7.2 | 0.6925 | 0.033 |
Table 4.
Experimental results of the ram-air secondary flow system.
Table 4.
Experimental results of the ram-air secondary flow system.
Mach Number |
|
|
---|
0.4 | 0.9254 | 0.0144 |
0.8 | 0.7368 | 0.0505 |
1.1 | 0.5733 | 0.0615 |
1.5 | 0.4553 | 0.1049 |
2.0 | 0.3104 | 0.1104 |
Table 5.
Experimental results of the submerged secondary flow system.
Table 5.
Experimental results of the submerged secondary flow system.
Mach Number |
|
|
---|
0.4 | 0.9716 | 0.02653 |
0.8 | 0.7351 | 0.01861 |
1.1 | 0.5918 | 0.04352 |
1.5 | 0.416 | 0.02509 |
2.0 | 0.2853 | 0.11008 |
Table 6.
The position of separation regions at the intake within the ram-air secondary flow system.
Table 6.
The position of separation regions at the intake within the ram-air secondary flow system.
Mach Number | Start Position | End Position |
---|
0.4 | Slices 1 | Slices 3 |
0.8 | Slices 1 | Slices 2 |
1.1 | Slices 1 | Slices 2 |
1.5 | Slices 1 | Slices 2 |
2.0 | Slices 1 | Slices 2 |
Table 7.
The position of separation regions at the intake within the submerged secondary flow system.
Table 7.
The position of separation regions at the intake within the submerged secondary flow system.
Mach Number | Start Position | End Position |
---|
0.4 | Slices 1 | Slices 1 |
0.8 | Slices 1 | Slices 3 |
1.1 | Slices 1 | Slices 4 |
1.5 | Slices 1 | Slices 3 |
2.0 | Slices 1 | Slices 3 |