【正文】 17 第四章 結(jié)束語 本文 以聲波方程為基礎(chǔ) ， 根據(jù)無擾動邊界假設(shè)， 對高速列車在隧道內(nèi)產(chǎn) 生的壓縮波 進行 計算，根據(jù)理論結(jié)果作了數(shù)值模擬 ，通過與文獻中理論和數(shù)值模擬結(jié)果的對比，顯示出了很好的一致性 。在此基礎(chǔ)上， 根據(jù)微氣壓波與壓縮波的梯度成正比的性質(zhì)， 提出 兩種 有源控制方法 。對間接控制方法， 在原聲場的聲源處設(shè)置一符號相反的聲源， 計算有源控制下的聲場，并做數(shù)值模擬，結(jié)果顯示了有源控制的可行性和高效性；對于直接控制方法，提出控制要點和實現(xiàn)方法。最后 設(shè)計了微壓波產(chǎn)生、觀測和有源控制實驗 。 傳統(tǒng)的控制微氣壓波的方法主要根據(jù)流體力學(xué)和氣動力學(xué)的知識，對隧道和列車作改進，都屬于無源控制方法，這些措施在降低微氣壓波 的幅度上都會遇到“瓶頸”，而有源控制在微氣壓波產(chǎn)生的聲源處或最后產(chǎn)生處添加控制源，可控的范圍和程度大大拓寬，但對控制細(xì)節(jié)要求比較精細(xì)。 本文的主要貢獻和創(chuàng)新在于 提出了微壓波有源控制的兩種方法；建立了微壓波有源控制系統(tǒng)的模型，并進行了數(shù)值模擬；設(shè)計了微壓波產(chǎn)生、觀測和有源控制實驗 。 作為 進一步的研究 ， 需要 建造系統(tǒng)， 做模型實驗， 然后進行 現(xiàn)場測量 ，最后將理論推導(dǎo)、數(shù)值模擬、模型實驗、實地測量綜合在一起，對其結(jié)果作驗證、對比與分析。 參考文獻 18 參考文獻 [1] C. Shin and W. Park, Numerical study of flow characteristics of the high speed train entering into a tunnel, Mechanics Research Communications 30(4) (2021) 287296. [2] 趙宇，高波，張兆杰，隧道壓力波的三維數(shù)值模擬，路基工程 ， 133 (2021) 1213。 [3] 李新霞，宋雷鳴，張新華，微氣壓波的產(chǎn)生機理與防治措施，噪聲與振動控制 ， 4 (2021) 7072。 [4] A. Yamamoto, Pressure variations, aerodynamic drag of train, and natural ventilation in Shinkansen type tunnel, Quarterly Report of RTRI 15(4) (1974) 207–214. [5] K. Matsuo, T. Aoki, S. Mashimo and E. Nakastu, Entry pression wave generated by a highspeed train entering a tunnel, Proceedings of the 9th Aerodynamics and Ventilation of Vehicle Tunnels. BHR Group Conference Series Publication 27 (1997) 925–934. [6] W. Woods and C. Pope, Secondary aerodynamic effects in rail tunnels during vehicle entry, Proceedings of the Second International Symposium on the Aerodynamics and Ventilation of Vehicle Tunnels, Cambridge (1976) 71–86. [7] M. Howe, Mach number dependence of the pression wave generated by a highspeed train entering a tunnel, Journal of Sound and Vibration 212(1) (1998) 2326. [8] M. Howe, The pression wave produced by a highspeed train entering a tunnel, Proceedings of the Royal Society 524 (1998a) 15231534. [9] M. Howe, The pression wave generated by a highspeed train at a vented tunnel entrance, J. Acoust. Soc. Am. 104(3) (1998) 11581164. [10] T. Yoon, S. Lee, J. Hwang and D. Lee, Prediction and validation on the sonic boom by a highspeed train entering a tunnel, Journal of Sound and Vibration 參考文獻 19 247(2) (2021) 195211. [11] S. Ozawa, T. Maeda, T. Matsumura, et al., Countermeasures to reduce micropressure waves radiating from exits of Shinkansen tunnels, 7th International Symposium on Aerodynamics and Ventilation of Vehicle Tunnels, Brighton, UK, 1991. [12] M. Bellenoue, B. Auvity and T. Kageyama, Blind hood effects on the pression wave generated by a train entering a tunnel, Experimental Thermal and Fluid Science 25(6) (2021) 397407. [13] T. Aoki, A. Vardy and J. Brown, Passive alleviation of micropressure waves from tunnel portals, Journal of Sound and Vibration 220(5) (1999) 921940. [14] J. Lee and J. Kim, Approximate optimization of highspeed train nose shape for reducing micropressure wave, Struct Multidisc Optim 35 (2021) 79–87. [15] M. Howe, Design of a tunnelentrance hood with multiple windows and variable crosssection, Journal of Fluids and Structures 17(8) (2021) 11111121. [16] A. Vardy and J. Brown, Influence of ballast on wave steepening in tunnels, Journal of Sound and Vibration 238 (2021) 595615. [17] M. Howe, Influence of train Mach number on the pression wave generated in a tunnelentrance hood, Journal of Engineering Mathematics 46 (2021) 147–163. [18] N. Sugimoto and T. Ogawa, Acoustic analysis of the pressure field in a tunnel, generated by entry of a train, Proceedings of the Royal Society of London A (1998) 454, 20832112. [19] 杜功煥，朱哲民，龔秀芬，聲學(xué)基礎(chǔ) [M]， (2021) 289293。 [20] R. Raghunathan, H. Kim and T. Setoguchi, Aerodynamics of highspeed railway train, Progress in Aerospace Sciences 38 (2021) 469514. [21] P. Ricco, A. Baron and P. Molteni, Nature of pressure waves induced by a highspeed train traveling through a tunnel, Journal of Wind Engineering and Industrial Aerodynamics 95(8) (2021) 781808. 致謝 20