發(fā)布時間：2018-01-11 06:23

  本文關(guān)鍵詞：內(nèi)波對水下聲信號時間相關(guān)性影響的數(shù)值和實驗研究　出處：《中國海洋大學(xué)》2015年博士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 線性內(nèi)波 時間相關(guān)半徑 匹配場 絕熱近似 耦合簡正波

【摘要】：海洋中內(nèi)波的存在會使聲信號的時間相關(guān)半徑變小。受物理介質(zhì)影響的信號時間相關(guān)半徑表明了信號由完全相關(guān)變?yōu)椴幌嚓P(guān)時經(jīng)過的時間尺度,它是聲納目標的檢測與識別、匹配場聲源定位以及水下通訊的重要技術(shù)指標。本文通過數(shù)值仿真和海上實驗數(shù)據(jù)處理,分析了內(nèi)波對聲場時間相關(guān)性的影響,得到了典型聲傳播條件下信號的匹配場時間相關(guān)半徑以及時間相關(guān)半徑在距離-深度空間上的分布。基于拋物方程(PE)理論,Monte-Carlo數(shù)值仿真了線性內(nèi)波存在時聲場的時間相關(guān)函數(shù),得到時間相關(guān)性的空間分布。在前人PE仿真所采用的凍結(jié)聲學(xué)環(huán)境模型的基礎(chǔ)上提出了一種非凍結(jié)的環(huán)境模擬方法,時間相關(guān)性的數(shù)值結(jié)果表明,在一定的頻率和接收距離范圍內(nèi),凍結(jié)模型依然可靠,但頻率越高,接收距離越遠,可靠性越低。對距離-深度空間各個位置處聲場時間相關(guān)性的理論和數(shù)值研究發(fā)現(xiàn),時間相關(guān)性在空間上的分布具有與聲場干涉條紋類似的結(jié)構(gòu),聲場會聚區(qū)的時間相關(guān)性優(yōu)于影區(qū),隨機噪聲的存在使這個結(jié)論更加明顯。此外,聲源頻率f、接收距離R和聲速擾動的統(tǒng)計標準差|δc|等參數(shù)的改變引起聲場干涉結(jié)構(gòu)的變化,導(dǎo)致時間相關(guān)半徑對其不再是對數(shù)坐標下的線性依賴。在Monte-Carlo研究的同時,提出了基于絕熱近似和耦合簡正波理論的統(tǒng)計方法。研究結(jié)果表明：深遠海聲傳播條件下,絕熱近似得到的匹配場時間相關(guān)半徑隨R、f和|δc|的冪指數(shù)關(guān)系與Monte-Carlo仿真和單向耦合方法的結(jié)果近似相同,但它高估了信號的時間相關(guān)半徑,且不能正確描述時間相關(guān)半徑的空間分布；淺海近距離聲傳播條件下,絕熱近似的計算結(jié)果具有一定的可靠性。本文發(fā)展的二維統(tǒng)計模型得到的匹配場時間相關(guān)半徑大于前人的三維模型,在本文參數(shù)范圍內(nèi),數(shù)值計算中一般考慮前5號內(nèi)波模態(tài)和幾十號簡正波就可以保證數(shù)值結(jié)果的可靠性,但要得到時間相關(guān)半徑的空間分布需要考慮更多的簡正波。對ASIAEX2001實驗的聲學(xué)數(shù)據(jù)處理后得到,當聲傳播路徑上出現(xiàn)強孤立子內(nèi)波時,聲場的時間相關(guān)半徑明顯降低,某些時刻300Hz信號的時間相關(guān)半徑低于20s,500Hz信號的時間相關(guān)半徑甚至降到l 0s內(nèi)；信號頻率越高,時間相關(guān)半徑越短：且聲場的時間相關(guān)半徑在深度上有明顯起伏。由兩個位置不同的聲源S1和S2發(fā)射的400Hz信號在接收位置R處的時間相關(guān)半徑不同,S2-R路徑的時間相關(guān)半徑比S1-R路徑長。這可能是由于內(nèi)波在S2-R路徑上的相位傳播速度小于S1-R路徑,聲源深度和地形的不同也可能對上述結(jié)果有所影響。PE仿真采用的凍結(jié)聲學(xué)環(huán)境忽略了內(nèi)波在傳播過程中波形和強度的變化,導(dǎo)致計算得到的時間相關(guān)半徑比實驗數(shù)據(jù)處理的結(jié)果要長。因此,建立更加完善的非凍結(jié)環(huán)境模型需要在發(fā)射與接收間布放足夠多的溫度鏈以監(jiān)測內(nèi)波傳播過程中的演變。
[Abstract]:The existence of internal waves in the ocean will make the time correlation radius of acoustic signal smaller. The time correlation radius of the signal affected by physical medium indicates the time scale of signal from complete correlation to irrelevant. It is an important technical index of sonar target detection and recognition, matching field source location and underwater communication. In this paper, the influence of internal wave on the time dependence of sound field is analyzed by numerical simulation and offshore experimental data processing. The time correlation radius of the matching field and the distribution of the time correlation radius in the distance-depth space are obtained under the typical sound propagation condition. The theory of the parabolic equation (PE) is used to obtain the distribution of the time-dependent radius of the signal in the range-depth space. The time correlation function of sound field in the presence of linear internal wave is simulated numerically by Monte-Carlo. Based on the frozen acoustic environment model used in previous PE simulation, a non-frozen environmental simulation method is proposed, and the numerical results of time correlation show that. In a certain range of frequency and receiving distance, the freezing model is still reliable, but the higher the frequency, the longer the receiving distance. The lower the reliability is, the more the theoretical and numerical study on the temporal correlation of sound field at each position in the range-depth space shows that the spatial distribution of temporal correlation has a structure similar to that of the interference fringes of sound field. The temporal correlation of the acoustic field convergence region is better than that of the shadow area, and the existence of random noise makes this conclusion more obvious. In addition, the sound source frequency f. The change of receiving distance R and the statistical standard deviation 未 c of the acoustic velocity disturbance leads to the change of the sound field interference structure. Therefore, the time-dependent radius is no longer a linear dependency in logarithmic coordinates. A statistical method based on adiabatic approximation and coupled normal wave theory is proposed. The results show that the time-dependent radius of the matching field obtained by adiabatic approximation depends on R. The power exponent relation of f and 未 c is approximately the same as that of Monte-Carlo simulation and unidirectional coupling method, but it overestimates the time-dependent radius of the signal. And the spatial distribution of time-dependent radius can not be correctly described. The calculated results of adiabatic approximation are reliable under the condition of near distance acoustic propagation in shallow water. The time correlation radius of the matching field obtained by the two-dimensional statistical model developed in this paper is larger than that of the previous three dimensional model. In the parameter range of this paper, the reliability of the numerical results can be guaranteed by considering the first 5 internal wave mode and the dozens of normal waves in the numerical calculation. But in order to obtain the spatial distribution of time-dependent radius, we need to consider more normal waves. After processing the acoustic data of ASIAEX2001 experiment, we can get that, when the strong soliton internal waves appear on the sound propagation path. The time correlation radius of sound field decreases obviously, and the time correlation radius of 300 Hz signal at some times is lower than that of 20 s ~ 500 Hz signal, even within 10 s. The higher the signal frequency. The shorter the time-dependent radius:. The time correlation radii of sound field fluctuate obviously in depth. The time correlation radii of 400 Hz signals transmitted by two different sound sources S1 and S2 are different at the receiving position R. The time-dependent radius of the S2-R path is longer than that of the S1-R path, which may be due to the fact that the phase propagation velocity of the internal wave in the S2-R path is lower than that in the S1-R path. The difference of sound source depth and topography may also affect the above results. The frozen acoustic environment used in PE simulation ignores the variation of the waveform and intensity of the internal wave in the process of propagation. The calculated time correlation radius is longer than that of experimental data processing. To establish a more perfect non-freezing environment model, enough temperature chains should be placed between the transmitter and receiver to monitor the evolution of internal wave propagation.
【學(xué)位授予單位】：中國海洋大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2015
【分類號】：P733.2;TB56

【相似文獻】

相關(guān)期刊論文 前10條

1 易學(xué)華;陳泗凱;賴鵬華;卜壽亮;鐘慶湖;;量子絕熱近似條件與量子幾何勢[J];量子電子學(xué)報;2014年02期

2 黃昆;多聲子復(fù)合理論中絕熱近似是否失效的問題[J];半導(dǎo)體學(xué)報;1980年01期

3 朱公先;過阻尼振子系統(tǒng)中役使原理與絕熱近似的關(guān)系及適用條件的探討——線性情況(Ⅰ)[J];北京師范學(xué)院學(xué)報(自然科學(xué)版);1988年02期

4 朱公先;過阻尼振子系統(tǒng)中役使原理與絕熱近似的關(guān)系及適用條件的探討——非線性情況(Ⅱ)[J];北京師范學(xué)院學(xué)報(自然科學(xué)版);1988年03期

5 曹力,吳大進;確定論系統(tǒng)快弛豫變量的精確消去和絕熱近似[J];華中理工大學(xué)學(xué)報;1992年02期

6 孫昌璞，趙樹人;時間軌道勢的理論分析[J];東北師大學(xué)報(自然科學(xué)版);1996年03期

7 劉倩,吳兆顏;高級量子絕熱近似理論在經(jīng)典物理中的應(yīng)用[J];萊陽農(nóng)學(xué)院學(xué)報;2004年04期

8 張新琴;夏秀文;羅小兵;;含時磁共振系統(tǒng)的精確解和絕熱近似解[J];大學(xué)物理;2011年07期

9 黃英華;;納機電系統(tǒng)的兩種解法比較——嚴格數(shù)值解和絕熱近似解[J];華北科技學(xué)院學(xué)報;2012年02期

10 朱公先;一維阻尼型弱非線性的運動系統(tǒng)中延遲響應(yīng)時間的計算法[J];杭州師范學(xué)院學(xué)報;1993年06期

相關(guān)博士學(xué)位論文 前2條

1 于小濤;內(nèi)波對水下聲信號時間相關(guān)性影響的數(shù)值和實驗研究[D];中國海洋大學(xué);2015年

2 趙梅生;量子信息理論中若干問題的研究[D];中國科學(xué)技術(shù)大學(xué);2007年

相關(guān)碩士學(xué)位論文 前3條

1 俞春明;量子絕熱近似中Berry相因子的幾何結(jié)構(gòu)[D];吉林大學(xué);2006年

2 秦江濤;量子系統(tǒng)Berry相位、A-A相位和PM相位的研究[D];魯東大學(xué);2015年

3 王英霞;強磁場中氫分子離子能級研究[D];中國石油大學(xué);2007年

，

本文編號：1408471