【正文】 本 科 畢 業(yè) 論 文 院 系 電子科學與工程系 題 目 高速列車進入隧道產(chǎn)生的微壓波及其控制研究 年 級 專 業(yè) 聲學 班 號 學 號 學生姓名 指導教師 職 稱 論文提交日期 摘要 高速 列車進入隧道產(chǎn)生的壓縮波傳播到 遂道出口時，會向出口外輻射一低頻脈沖波，這種脈沖波產(chǎn)生的爆炸 聲可達 140~150dB 甚至更高的聲壓級，對周邊環(huán)境造成嚴重危害，這種低頻脈沖波被稱為 “ 微氣壓波 ” 。 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，并 對間接控制方法作了理論分析和數(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，提出了控制要點和實現(xiàn)方法。最后 設(shè)計了微壓波產(chǎn)生、觀測和有源控制實驗 。 ii Abstract When the pression wave induced by a highspeed train entering a tunnel propagates to the tunnel exit, a lowfrequency pulse wave is radiated. The sound level of explosions of this pulse, which causes serious damages to the surrounding environment, is up to 140 ~ 150 dB even higher. This lowfrequency pulse is called microwave pressure. Based on acoustic equation and the undisturbed boundary assumption, the pression wave generated by a highspeed train entering a tunnel is calculated in this paper. Numerical simulation is then made according to theoretical results. The contrasts with those results in the literature show a good agreement. On the basis of the conclusion— the microwave is proportional to the pressure gradient of the pression wave, two active control methods are proposed. The theoretical analysis and numerical simulation are made according to the indirect control method and the results show the feasibility and efficiency. For direct control method, the key points of the method and the general implementation program are put forward. Finally, the experiments of the generation, observation and active control of the micropressure waves are designed. iii 目錄 摘要 .................................................................................................................................. i Abstract ............................................................................................................................ ii 第一章 引言 ................................................................................................................. 1 ......................................................................................................... 1 ........................................................................................ 1 .................................................................................................. 3 ......................................................................................................... 4 第二章 理論推導和數(shù)值模擬 ........................................................................................ 6 ...................................................................................................... 6 .............................................................................................................. 10 ..................................................................................................................... 11 第三章 微壓波有源控制 ............................................................................................. 12 .................................................................................................... 12 .............................................................................................................. 13 .............................................................................................................. 14 第四章 結(jié)束語 ........................................................................................................... 17 參考文 獻 ........................................................................................................................ 18 致謝 .....................................................................................................