Explorative Gradient Method-Based Research on the Optimization of Nozzle Flow-guiding Devices

Wang, Y.; Huang, L.; Jia, Q.; Yang, Z.

doi:10.47176/jafm.16.08.1725

Explorative Gradient Method-Based Research on the Optimization of Nozzle Flow-guiding Devices

Document Type : Regular Article

Authors

¹ School of Automotive Studies, Tongji University, 4800 Cao An Rd., Jiading, Shanghai 201804, China

² Shanghai Key Lab of Vehicle Aerodynamics and Vehicle Thermal Management Systems, Tongji University, 4800 Cao An Rd., Jiading, Shanghai 201804, China

10.47176/jafm.16.08.1725

Abstract

Low-frequency buffeting is a common problem in automobile wind tunnels, it induces pulsations of pressure and velocity in the test section. A 1:15 3/4 open-jet return-type scaled wind tunnel was used for this research, and numerical simulations and tests were implemented to study the flow characteristics of the jet shear layer in a model wind tunnel. The results show that guide devices on the inner wall of the nozzle can effectively reduce the low-frequency buffeting, but the presence of the devices deteriorated the axial static pressure gradient of the flow in the test section. The shape of the guide devices was optimized through the Explorative Gradient Method, and numerical simulations were carried out. An optimal shape can effectively reduce the low-frequency buffeting and ensure flow field uniformity in the test section. Finally, the reliability of the numerical simulation and the practicability of the optimal case were verified through a hot wire test and a microphone test.

Keywords

Main Subjects

Computational Fluid Dynamics

References

Amandolèse, X., & Vartanian, C. (2010). Reduction of 3/4 open jet low-frequency fluctuations in the S2A wind tunnel. Journal of wind engineering and industrial aerodynamics, 98(10-11), 568-574. https://doi.org/10.1016/j.jweia.2010.04.011##

Bartel, H. W., & McAvoy, J. M. (1981). Cavity oscillation in cruise missile carrier aircraft. Lockheed-Georgia Co Marietta Structures Technology Div.##

Blumrich, R., Widdecke, N., Wiedemann, J., Michelbach, A., Wittmeier, F., & Beland, O. (2015). New FKFS technology at the full-scale aeroacoustic wind tunnel of University of Stuttgart. SAE International Journal of Passenger Cars-Mechanical Systems, 8(2015-01-1557), 294-305. https://doi.org/10.4271/2015-01-1557##

Cazemier, W., Verstappen, R. W. C. P., & Veldman, A. E. P. (1998). Proper orthogonal decomposition and low-dimensional models for driven cavity
flows. Physics of Fluids, 10(7), 1685-1699. https://doi.org/10.1063/1.869686##

Evert, F., & Miehling, H. (2004). Active suppression of buffeting at the Audi AAWT: Operational experiences and enhancements of the control scheme. SAE Transactions, 419-430. https://doi.org/10.4271/2004-01-0804##

Jia, Q., Huang, L., Zhu, Y., Rashidi, M. M., Xu, J., & Yang, Z. (2021). Experimental research of active control optimization on a 3/4 open-jet wind tunnel’s jet section. Alexandria Engineering Journal, 60(2), 2265-2278. https://doi.org/10.1016/j.aej.2020.12.022##

Künstner, R., Potthoff, J., & Essers, U. (1995). The aero-acoustic wind tunnel of Stuttgart University. SAE Transactions, 1119-1135.##

Li, Y., Cui, W., Jia, Q., Li, Q., Yang, Z., Morzyński, M., & Noack, B. R. (2022). Explorative gradient method for active drag reduction of the fluidic pinball and slanted Ahmed body. Journal of Fluid Mechanics, 932. https://doi.org/10.1017/jfm.2021.974##

McKay, M. D., Beckman, R. J., & Conover, W. J. (2000). A comparison of three methods for selecting values of input variables in the analysis of output from a computer code. Technometrics, 42(1), 55-61. https://doi.org/10.2307/1268522##

Nelder, J. A., & Mead, R. (1965). A simplex method for function minimization. The computer Journal, 7(4), 308-313. https://doi.org/10.1093/comjnl/7.4.308##

Pott-Pollenske, M., Von Heesen, W., & Bergmann, A. (2012). Acoustical preexamination work and characterization of the low noise wind tunnel DNW-NWB. 18th AIAA/CEAS Aeroacoustics Conference (33rd AIAA Aeroacoustics Conference). https://doi.org/10.2514/6.2012-2175##

Press, W. H., Teukolsky, S. A., Vetterling, W. T., & Flannery, B. P. (2007). Numerical Recipes 3rd Edition: the Art of Scientific Computing. Cambridge university press.##

Rashidi, M. M., Jia, Q., Yang, Z., Bao, D., & Zhu, Y. (2019). On the low frequency pressure fluctuation in a 3/4 open jet automotive wind tunnel. Journal of Applied Fluid Mechanics, 12(5), 1359-1369. https://doi.org/10.29252/jafm.12.05.29530##

Rossiter, J. E. (1964). Wind-tunnel experiments on the flow over rectangular cavities at subsonic and transonic speeds.##

Stoll, D., & Wiedemann, J. (2018). Active Crosswind Generation and Its Effect on the Unsteady Aerodynamic Vehicle Properties Determined in an Open Jet Wind Tunnel. SAE International Journal of Passenger Cars-Mechanical Systems, 11(5), 429-447. https://doi.org/10.4271/2018-01-0722##

Von Helmholtz, H. (1912). On the Sensations of Tone as a Physiological Basis for the Theory of Music. Longmans, Green.##

Zheng, Z. (2009). Study and control of buffeting phenomenon for automotive aero-acoustic wind tunnel. [Master's Thesis, Tongji University]. Shanghai, China. [in Chinese].##

Zheng, Z., & Yang, Z. (2008). Experimental Investigations of Effects of Collector on Performances of Automotive Wind Tunnel (No. 2008-01-1206). SAE Technical Paper.##