Numerical Analysis of Unsteady Characteristics of the Second Throat of a Transonic Wind Tunnel
The unsteady characteristics of the second throat of a transonic wind tunnel have an important influence on the design and test of the wind tunnel. Therefore, the forced oscillation characteristics were studied by a numerical simulation method. The governing equation was the viscous compressible uns...
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MDPI AG
2023-11-01
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| author | Chenghua Cong Honggang Qin Xingyou Yi |
| author_facet | Chenghua Cong Honggang Qin Xingyou Yi |
| author_sort | Chenghua Cong |
| collection | DOAJ |
| description | The unsteady characteristics of the second throat of a transonic wind tunnel have an important influence on the design and test of the wind tunnel. Therefore, the forced oscillation characteristics were studied by a numerical simulation method. The governing equation was the viscous compressible unsteady Navier–Stokes equation. Under the sinusoidal pressure disturbance of the computational domain exit, the shock wave presents a clear forced oscillation state, and the shock wave periodically changes its position. Under a pressure disturbance of 1%, the shock wave displacement reaches 150 mm. Additionally, overshoot occurs when the shock moves upstream or downstream. The shock-boundary layer interference is very sensitive to the motion characteristics of the shock wave, resulting in a transformation of the flow field symmetry. The flow field downstream of the shock wave exhibits periodic structural changes. Compared with the pressure change at the outlet, the pressure change near the shock wave has a phase delay. The increasing disturbance near the shock wave shows a clear amplification effect. The pressure disturbance near the shock wave had an obvious amplification effect, and its fluctuation amount reached 16% under the pressure disturbance of 1%. The variation trend of the second throat wall force, wavefront Mach number, and Mach number in the test section with time is similar to that of the downstream disturbance, but it does not have a complete follow-up effect, which indicates that the pressure disturbance can propagate into the test section through the boundary layer or the shock gap. Nevertheless, the second throat choking can still control the Mach number stability of the test section. The dynamic characteristics of shock oscillation are related to the amplitude and frequency of the applied pressure disturbance. The shock displacement decreases with the increase in the excitation frequency. When the excitation frequency is higher than 125 Hz, the flow field basically does not change. |
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| last_indexed | 2024-03-09T17:07:14Z |
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| spelling | doaj.art-45a18e6b9a8b40c79fd2d6622e9e004f2023-11-24T14:22:52ZengMDPI AGAerospace2226-43102023-11-01101195610.3390/aerospace10110956Numerical Analysis of Unsteady Characteristics of the Second Throat of a Transonic Wind TunnelChenghua Cong0Honggang Qin1Xingyou Yi2Key Laboratory of Unsteady Aerodynamics and Flow Control of Ministry of Industry and Information Technology, College of Aerospace Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, ChinaFacility Design and Instrumentation Institute, China Aerodynamics Research and Development Center, Mianyang 621000, ChinaFacility Design and Instrumentation Institute, China Aerodynamics Research and Development Center, Mianyang 621000, ChinaThe unsteady characteristics of the second throat of a transonic wind tunnel have an important influence on the design and test of the wind tunnel. Therefore, the forced oscillation characteristics were studied by a numerical simulation method. The governing equation was the viscous compressible unsteady Navier–Stokes equation. Under the sinusoidal pressure disturbance of the computational domain exit, the shock wave presents a clear forced oscillation state, and the shock wave periodically changes its position. Under a pressure disturbance of 1%, the shock wave displacement reaches 150 mm. Additionally, overshoot occurs when the shock moves upstream or downstream. The shock-boundary layer interference is very sensitive to the motion characteristics of the shock wave, resulting in a transformation of the flow field symmetry. The flow field downstream of the shock wave exhibits periodic structural changes. Compared with the pressure change at the outlet, the pressure change near the shock wave has a phase delay. The increasing disturbance near the shock wave shows a clear amplification effect. The pressure disturbance near the shock wave had an obvious amplification effect, and its fluctuation amount reached 16% under the pressure disturbance of 1%. The variation trend of the second throat wall force, wavefront Mach number, and Mach number in the test section with time is similar to that of the downstream disturbance, but it does not have a complete follow-up effect, which indicates that the pressure disturbance can propagate into the test section through the boundary layer or the shock gap. Nevertheless, the second throat choking can still control the Mach number stability of the test section. The dynamic characteristics of shock oscillation are related to the amplitude and frequency of the applied pressure disturbance. The shock displacement decreases with the increase in the excitation frequency. When the excitation frequency is higher than 125 Hz, the flow field basically does not change.https://www.mdpi.com/2226-4310/10/11/956transonic wind tunnelsecond throatshock waveforced oscillationpressure perturbationphase delay |
| spellingShingle | Chenghua Cong Honggang Qin Xingyou Yi Numerical Analysis of Unsteady Characteristics of the Second Throat of a Transonic Wind Tunnel Aerospace transonic wind tunnel second throat shock wave forced oscillation pressure perturbation phase delay |
| title | Numerical Analysis of Unsteady Characteristics of the Second Throat of a Transonic Wind Tunnel |
| title_full | Numerical Analysis of Unsteady Characteristics of the Second Throat of a Transonic Wind Tunnel |
| title_fullStr | Numerical Analysis of Unsteady Characteristics of the Second Throat of a Transonic Wind Tunnel |
| title_full_unstemmed | Numerical Analysis of Unsteady Characteristics of the Second Throat of a Transonic Wind Tunnel |
| title_short | Numerical Analysis of Unsteady Characteristics of the Second Throat of a Transonic Wind Tunnel |
| title_sort | numerical analysis of unsteady characteristics of the second throat of a transonic wind tunnel |
| topic | transonic wind tunnel second throat shock wave forced oscillation pressure perturbation phase delay |
| url | https://www.mdpi.com/2226-4310/10/11/956 |
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